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Waterdrop King Tank
- Gravity
- Point of use
- City water
- Complete system
- Listed
$168.99as of 2026-09-04MSRP $229.99 as of 2026-09-04
Secondary sourceVerified 2026-09-04Retailer listing
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Our verdict on the Waterdrop King Tank
The Waterdrop King Tank is a 2.25-gallon stainless-steel countertop gravity filter that needs no electricity, no drain and no plumbing, and IAPMO R&T lists all four of its system models (WD-TK, WD-TK-F, WD-TK-S, WD-TK-FS) on file W-13936 as lead-free under NSF/ANSI 372 — a materials standard covering the lead content of the wetted parts, not a contaminant-reduction claim, and searches of the NSF, IAPMO R&T and WQA directories on 2026-09-04 turned up no reduction-performance listing for the system or its elements.[1][2][3][4][5][6]
Best for
- Renters and apartment dwellers on municipal water who cannot plumb anything in — the system sits on a counter and needs no electricity and no drain
- Households of up to four people, which is the size Waterdrop states the 2.25-gallon capacity is meant to serve
- Off-grid cabins, RVs and emergency kits where the water has already been made microbiologically safe by boiling or disinfection
Not for
- Anyone treating water of unknown microbiological quality — an untested well, spring or river — without adequate disinfection before or after the system, which the user manual explicitly warns against
- Anyone who needs a lower TDS reading: Waterdrop states the system is not designed to primarily reduce TDS and points TDS buyers at its reverse-osmosis range instead
- Buyers who need third-party certified contaminant-reduction performance: the only directory listing found covers lead content of the materials under NSF/ANSI 372, and every removal percentage on the box is the brand's own lab claim
Secondary sourceVerified 2026-09-04IAPMO listingManufacturer datasheetBrand officialRetailer listingNSF listingWQA listing
Certification check: Waterdrop King Tank
Listed by IAPMO R&T under NSF/ANSI 372, checked in the certifier directories as of 2026-09-04.
- IAPMO R&T
- NSF/ANSI 372
IAPMO R&T and WQA certify products against the same NSF/ANSI standards as NSF, so a listing from either one is an equivalent third-party certification, not a lesser one.
| Directory | Result | Listing |
|---|---|---|
| NSF | No listing found (checked 2026-09-04) | View listing |
| IAPMO R&T | Listing found (checked 2026-09-04) | View listing |
| WQA | No listing found (checked 2026-09-04) | View listing |
Claimed vs. certified: Waterdrop King Tank
| Contaminant | Status | Third-party listing | What the brand says |
|---|---|---|---|
| Chlorine | Marketed only | No entry |
|
| Chlorine, fluoride, heavy metals, rust and other impurities (combined) | Marketed only | No entry |
|
| Chlorine, fluoride, odours and sediment (replacement element set) | Marketed only | No entry |
|
| Chlorine, taste and odour; lead content of the materials | Marketed only | No entry |
|
| Heavy metals, sediment, rust, soil and other impurities | Marketed only | No entry |
|
| PFAS, chlorine and lead | Marketed only | No entry |
|
| Lead content of the wetted materials (a materials standard, not a contaminant-reduction claim) | Certified only |
| No entry |
What the Waterdrop King Tank does not do
Waterdrop's own user manual instructs owners not to run microbiologically unsafe water or water of unknown quality through the King Tank without adequate disinfection before or after the system. The Waterdrop King Tank's recorded operating limits are Carbon element capacity (both black elements combined) up to 6,000 gallons, Fluoride element capacity (both white elements combined, WD-TK-F and WD-TK-FS only) up to 1,000 gallons, Operating temperature at least 40 °F and up to 100 °F, verified 2026-09-03.
Waterdrop's own user manual instructs owners not to run microbiologically unsafe water or water of unknown quality through the King Tank without adequate disinfection before or after the system.[1]
Primary sourceVerified 2026-09-03Manufacturer datasheet
The King Tank does not lower total dissolved solids. Waterdrop states the system 'is not designed to primarily reduce TDS' and directs buyers who want a lower TDS reading to its reverse-osmosis range.[1][2]
Primary sourceVerified 2026-09-03Brand officialManufacturer datasheet
The certification that IAPMO R&T lists for the King Tank covers the lead content of the wetted materials under NSF/ANSI 372 only. That listing certifies no contaminant-reduction performance, and the manual's own certification footer says exactly that: 'System Certified by IAPMO R&T against NSF/ANSI Standard 372 (<=0.25 lead).'[1][2]
Primary sourceVerified 2026-09-03IAPMO listingManufacturer datasheet
The two chambers are not sealed to each other. Waterdrop states there is no water-tight seal between the upper and lower chambers, so water can spill from the join if the upper chamber is refilled before the lower chamber is emptied.[1][2]
Primary sourceVerified 2026-09-03Manufacturer datasheetBrand official
Fluoride reduction is only available on the WD-TK-F and WD-TK-FS configurations, which ship with the two white fluoride elements; the WD-TK and WD-TK-S ship with carbon elements only, and Waterdrop notes that its fluoride removal test was run under standard third-party laboratory conditions and that actual results may vary.[1]
Primary sourceVerified 2026-09-03Manufacturer datasheet
Operating limits
| Parameter | Limit | What it means |
|---|---|---|
| Carbon element capacity (both black elements combined) | up to 6,000 gallons[1][2] | Waterdrop says the pair filters up to 6,000 gallons in total and that the elements must be replaced once that capacity is reached; actual replacement time varies with local water quality. Primary sourceVerified 2026-09-03Manufacturer datasheetBrand official |
| Fluoride element capacity (both white elements combined, WD-TK-F and WD-TK-FS only) | up to 1,000 gallons[1][2] | Primary sourceVerified 2026-09-03Manufacturer datasheetBrand official |
| Operating temperature | at least 40 °F and up to 100 °F[1] | Waterdrop's warranty explicitly excludes 'use in abnormal operation temperature conditions, conditions outside of the listed operating parameters', so running the system outside 40-100 °F voids cover as well as risking the components. Primary sourceVerified 2026-09-03Manufacturer datasheet |
Do not buy it for these situations
Well waterNot for untested private well, spring or surface water. The manual's standing instruction is 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system', and Waterdrop publishes no bacteria, cyst or virus reduction rating for the King Tank elements. Owners on such supplies need disinfection (boiling, chlorination or UV) in addition to, not instead of, this filter.[1]
Primary sourceVerified 2026-09-03Manufacturer datasheet
Fit and sizing: Waterdrop King Tank
The Waterdrop King Tank is a gravity unit installed at the point of use, for city water.
| Form factor | Gravity |
|---|---|
| Installed at | Point of use (one fixture) |
| Water source | City water |
| Household size | 1–4 people[1] Secondary sourceVerified 2026-09-04Retailer listing |
| Dimensions | 20.4 in H × 8.5 in W × 8.5 in D[1][2] Primary sourceVerified 2026-09-04Brand official |
| Operating temperature | 40–100 °F[1] Primary sourceVerified 2026-09-03Manufacturer datasheet |
| Needs electricity | No[1][2] Primary sourceVerified 2026-09-04Brand officialManufacturer datasheet |
| Needs a drain | No[1][2] Primary sourceVerified 2026-09-04Brand official |
What the Waterdrop King Tank really costs
The Waterdrop King Tank costs $168.99 as of 2026-09-04. Over ten years, including installation and replacement elements, the recorded total is $405.96.
Replacement schedule
| Element | Replace | Cost per year |
|---|---|---|
| WD-BB9 black carbon elements (pair) — fitted to every King Tank SKU | every 6,000 gallons | $26.33 |
| PF-2-C white fluoride elements (pair) — WD-TK-F and WD-TK-FS only | every 1,000 gallons | Not recorded |
Primary sourceVerified 2026-09-04Manufacturer datasheetBrand officialRetailer listing
Ten-year cost of ownership
| Purchase price (as of 2026-09-04) | $168.99 |
|---|---|
| Replacement elements, 10 × $26.33/year | $263.30 |
| Sum of the lines above (as of 2026-09-04) | $432.29 |
| Recorded ten-year total | $405.96 |
Warranty: One-year warranty covering defects in materials and workmanship from the original date of purchase; Waterdrop will replace or repair a part deemed defective. It excludes misuse, abnormal operating temperatures, use outside the listed operating parameters and commercial use, and it does not apply to filter cartridges because element life varies with incoming water quality. (1 years)[1][2]
Primary sourceVerified 2026-09-03Manufacturer datasheetBrand official
Money-back guarantee: 30-day worry-free returns advertised on Waterdrop's own product page, alongside 30-day price protection. (30 days)[1]
Primary sourceVerified 2026-09-04Brand official
Installing the Waterdrop King Tank
Installing the Waterdrop King Tank is an easy job. DIY install, verified 2026-09-03.
Tools required
- Wrench (supplied in the box)
Primary sourceVerified 2026-09-03Manufacturer datasheet
Manufacturer documentation
- Install manual: https://m.media-amazon.com/images/I/919zL+VUpKL.pdf (accessed 2026-09-03)
- Install video: https://www.youtube.com/watch?v=sFuWMmShyas (accessed 2026-09-03)
Ongoing maintenance
- Clean the whole system — remove the elements, spigot and other attached components first, then wash the chambers with water and dish soap — every 1 months
- If the system will stand unused for more than three days, empty both chambers, remove all filtration elements and let the components dry
- Re-flush an element that has been stored before putting it back into service, and never freeze one
- Check that the spigot is closed before the first operation and after each re-priming
Primary sourceVerified 2026-09-03Manufacturer datasheet
Track record: Waterdrop King Tank
Amazon (WD-TK / King Tank Series variation family) shows 4.5 out of 5 from 1,469 reviews as of 2026-09-04; Waterdrop (King Tank, Without Stand) shows 4.8 out of 5 from 20 reviews as of 2026-09-03; Waterdrop (King Tank, With Stand) shows 4.6 out of 5 from 37 reviews as of 2026-09-03.
| Source | Rating | Reviews | As of |
|---|---|---|---|
| Amazon (WD-TK / King Tank Series variation family) | 4.5 out of 5 | 1,469 | 2026-09-04 |
| Waterdrop (King Tank, Without Stand) | 4.8 out of 5 | 20 | 2026-09-03 |
| Waterdrop (King Tank, With Stand) | 4.6 out of 5 | 37 | 2026-09-03 |
What owners praise
Amazon's aggregated review summary reports that buyers find the build quality and appearance good and the filtered water good-tasting, with one reviewer noting it removed metallic flavours, and that they consider it good value — one comparing it favourably with Berkey filters.[1]
Secondary sourceVerified 2026-09-04Amazon review
A commenter in an r/OffGrid thread about this system reported owning that exact filter system, said it works very well physically, rated it every bit as good as a Berkey, and singled out the included sight glass and metal spigot. The thread's original poster — a different user — is the one who linked the WD-TK Amazon listing.[1]
Secondary sourceVerified 2026-09-04Reddit thread
Amazon reviewers repeatedly single out the stainless build and the sight-glass spigot, including a long-term Big Berkey owner who wrote that the Waterdrop's stainless container is nicer quality than the Berkey they had used for ten years and that the water-level spigot, with its red indicator dot, makes the level easier to read.[1]
Secondary sourceVerified 2026-09-04Amazon review
What owners complain about
Amazon's aggregated review summary records divided opinion on leakage — some buyers report no issues, others experience leaks — which matches the manufacturer's own statement that the upper and lower chambers are not sealed to each other.[1]
Secondary sourceVerified 2026-09-04Amazon review
Filtration feedback on Amazon is mixed: many buyers say the water comes out clean, but at least one reports the system did not remove fluoride — a configuration trap, since the WD-TK and WD-TK-S ship without the white fluoride elements at all.[1]
Secondary sourceVerified 2026-09-04Amazon review
A Google Shopping reviewer rating the system 3/5 said the filtering process takes too long for them and that the rubber feet fall off the stand whenever the unit is moved.[1]
Secondary sourceVerified 2026-09-03Retailer listing
Shoppers weighing the King Tank against Berkey and ProOne in r/WaterTreatment said certification was the deciding factor they were looking for, and one commenter in the same thread dismissed gravity filters generally as overpriced relative to a pitcher.[1]
Secondary sourceVerified 2026-09-03Reddit thread
The Waterdrop King Tank against its family and its rivals
The Waterdrop King Tank has one sibling in its family: WD-TK-A-FS. Search demand pairs it with Berkey Big Berkey.
IAPMO R&T file W-13936 names WD-TK, WD-TK-F, WD-TK-S and WD-TK-FS individually on the certificate, so its NSF/ANSI 372 lead-content listing covers all four King Tank system configurations rather than being extended from one of them. That listing is a materials standard and certifies no reduction performance. It does not reach the replacement elements sold separately: searches for the WD-BB9 carbon element and for BB9-2 returned no listing in the NSF directory or the IAPMO R&T directory, and no listing in WQA's, on 2026-09-04.[1][2][3][4]
Primary sourceVerified 2026-09-04IAPMO listingNSF listingWQA listing
The rest of the family
| Model | What differs |
|---|---|
| WD-TK-A-FS | A separate King Tank line — WD-TK-A, WD-TK-A-S and WD-TK-A-FS — sold alongside this one. It is also 2.25 gallons and also ships with four filters and a stand, but on 2026-09-03 it sold for $169.99 on Amazon against $199.99 for the WD-TK-FS, and rated 4.4 from 740 reviews against 4.5 from 1,469. Waterdrop does not publish what differs between the TK and TK-A lines, so a shopper searching 'King Tank' can land on either. |
Cross-shopped against
| Rival | Why this pair |
|---|---|
| Berkey Big Berkey | The People Also Ask block on the live SERP for 'waterdrop king tank' (2026-09-03) leads with 'Is Waterdrop as good as Berkey?', and 'waterdrop king tank vs berkey' is a related search on both the primary and the review SERP and is carried in this record's secondary cluster. Amazon's 'Customers who viewed this item also viewed' module on the WD-TK listing (2026-09-04) places the Big Berkey 2.25-gallon system directly beside it at $367.00. |
Waterdrop King Tank questions, answered
Is the Waterdrop King Tank NSF certified?
Verified health claim
Partly, and the part matters. IAPMO R&T — an equivalent certifier to NSF, certifying to the same NSF/ANSI standards — lists all four King Tank system models (WD-TK, WD-TK-F, WD-TK-S, WD-TK-FS) on file W-13936 as a 'Lead Free Water Filtration Product' certified to NSF/ANSI 372, which limits the lead content of the wetted materials to a weighted average of 0.25% or less. That is a materials standard: it says the tank and spigot will not add lead to your water, not that the filter removes anything. Waterdrop itself claims more than that, and it does so on its own site as well as on Amazon: the Specification table on waterdropfilter.com's King Tank page gives 'Certification — NSF/ANSI 42 & 372', and the Amazon listing spells the same escalation out as 'the black carbon filter is certified against NSF/ANSI 42 for the reduction of chlorine, taste and odor'. We searched for an NSF/ANSI 42 listing on 2026-09-04 and found none: NSF's Drinking Water Treatment Units directory returned no match for WD-TK or WD-BB9, IAPMO R&T's directory returned only the NSF/ANSI 372 file for those models, and WQA's listings returned no result. Waterdrop's own user manual states only 'System Certified by IAPMO R&T against NSF/ANSI Standard 372'.
Can I use the Waterdrop King Tank with well water, river water or rainwater?
Verified health claim
Not on its own. Waterdrop's user manual states twice — in the installation steps and again in the operating tips — 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system.' Waterdrop publishes no bacteria, cyst or virus reduction rating for the King Tank elements,. In the r/OffGrid thread about this exact system, a commenter gave the same answer to someone hoping to drink filtered river water: it will address heavy metals, but it is not rated for bacteria or virus treatment and should be used alongside boiling, not instead of it. If your supply is an untested private well, a spring or surface water, disinfect it — boil, chlorinate or use UV — and treat the King Tank as taste, odour and sediment polish on top.
Does the Waterdrop King Tank remove fluoride?
Verified health claim
Only if you buy a configuration that includes the two white fluoride elements — the WD-TK-F or the WD-TK-FS. The WD-TK and WD-TK-S ship with the two black carbon elements only, and the manual marks the fluoride element as an excluded part on those two models and as 'Only applicable to WD-TK-F/WD-TK-FS' in the installation steps. Where the fluoride elements are fitted, Waterdrop claims the set 'reduces chlorine, fluoride, odors, and sediments', and the manual adds its own caveat: 'The fluoride removal test is carried out under the standard conditions of a third-party laboratory, and actual results may vary.' No certifier directory we searched on 2026-09-04 — NSF, IAPMO R&T or WQA — listed the King Tank or its elements for fluoride reduction, so the fluoride claim rests on the brand's own laboratory testing.
Why does the TDS reading not drop after filtering?
Verified health claim
Because the King Tank is not built to lower TDS, and Waterdrop says so. Its product FAQ states 'This system is not designed to primarily reduce TDS' and the manual explains that the gravity-fed system 'filters out harmful substances while preserving beneficial minerals' — the dissolved calcium and magnesium a TDS meter counts pass straight through an activated-carbon element. Waterdrop directs buyers who want a lower TDS number to its reverse-osmosis range instead. A TDS meter is therefore the wrong instrument for judging whether this filter is working.
How often do you replace Waterdrop King Tank filters, and what do they cost?
Waterdrop rates the pair of black carbon elements at up to 6,000 gallons in total and the pair of white fluoride elements at up to 1,000 gallons in total, and says to replace them once that capacity is reached rather than on a calendar — 'the actual replacement time might vary according to the local water quality'. Direct from Waterdrop on 2026-09-04, a 2-pack of WD-BB9 black elements was $78.99 (a 4-pack $111.99), a 2-pack of white fluoride elements was $56.99 but shown as sold out, and a combined set of two black plus two fluoride elements was $94.99. Waterdrop's own Amazon copy frames 6,000 gallons as about three years of household use, which works out at roughly $26 a year for carbon elements.
How fast does the Waterdrop King Tank filter water?
Waterdrop publishes no flow-rate figure for the King Tank, so this record does not put a number on it: there is none in the manual's specification table, none on either product page and none on the Amazon listing. What the manual does explain is why the rate changes as a batch runs — 'Because this system is gravity-fed, as the water level in the upper chamber drops, the filtering process naturally slows down because there is less water pressure available to force water through the elements' — and it adds that one to two inches of water left in the upper chamber at the end of a batch is normal rather than a fault. Waterdrop also asks you to flush the elements for at least a minute before first use, and a slow initial flow before the carbon is fully wetted is expected. The number that is published is the batch itself: 2.25 gallons, which Waterdrop states meets the demand of a family of four.
Does the Waterdrop King Tank need electricity, plumbing or a drain?
None of the three. Waterdrop's specification table records 'Electricity Required: No', the product page states there is 'no electricity or wastewater', and the whole installation in the manual is six manual steps using the wrench supplied in the box — fit the lid knob, fit the spigot, flush the elements at a tap, install the elements, stack the chambers, then flush the assembled system two or three times. That is what makes it a realistic option for renters: nothing is cut, drilled or plumbed. It does need counter space of about 8.5 inches square and 20.4 inches of height.
Is Waterdrop a Chinese company?
The King Tank is made in China by Qingdao Ecopure Filter Co., Ltd., which the manual names on its back page alongside 'Made in China'. That same company is the listee on IAPMO R&T file W-13936 and on NSF's own listings for Qingdao Ecopure under NSF/ANSI 42, 53 and 401 for other products, and Waterdrop operates a US storefront and US customer support. Country of manufacture is not a proxy for certification status: what a directory lists, for which standard, on which date is the check that actually tells you something, and for this product that check returns an NSF/ANSI 372 lead-content listing and nothing else.
Is the Waterdrop King Tank as good as a Berkey?
Verified health claim
On price and hardware the King Tank undercuts it; on certified performance neither brand's marketing settles the question, and this record only checked the Waterdrop. On Amazon on 2026-09-04 the King Tank (WD-TK) sold for $168.99 against $367.00 for the Big Berkey, both holding 2.25 gallons, and both carried a 4.5-star average — the King Tank from 1,469 ratings, the Big Berkey from 4,214. An owner in r/OffGrid called the Waterdrop 'every bit as good as the berkey' and noted that the sight glass and metal spigot are included rather than bought separately, and a verified-purchase Amazon reviewer who had run a Big Berkey for ten years wrote that the Waterdrop's stainless container is the nicer quality of the two. Waterdrop's own listing states the system 'is not sourced by or sponsored by Berkey' and that Waterdrop is an independent brand. On certification the honest answer is narrower than either brand's marketing: the King Tank's only directory listing is IAPMO R&T file W-13936 for NSF/ANSI 372 lead content, and we found no contaminant-reduction listing for it in the NSF, IAPMO R&T or WQA directories on 2026-09-04. We have not run the same three lookups against the Big Berkey in this record, so treat this as a comparison of price, capacity and owner reports, not of certified performance.
Sources and data report: Waterdrop King Tank
Every figure above is taken from the highest-trust source that carries it and re-derived from that source by a separate check. How we verify product data.
What we could not establish, and why
| Field | Why it is blank |
|---|---|
| certified.certIndexKey | Our certification index has one Waterdrop file (data/certifications/by-brand/waterdrop.json), and all 19 records in it are Ecolife EFF-60xxS refrigerator filters. No King Tank, WD-TK, ECF-7088S, BB9-2 or WD-BB9 entry exists to join to, so there is no index key to record. This says nothing about certification: the live IAPMO R&T lookup found file W-13936 covering all four King Tank models. |
| fit.bathroomsServed | A countertop gravity filter is not sized by bathroom count. Waterdrop describes people served ('a family of 4 people') on both the brand page and the Amazon listing, and neither the manual nor either product page publishes a bathroom figure. |
| fit.serviceFlowGpm | Waterdrop publishes no flow rate anywhere — not in the manual's specification table, not on either product page, not on the Amazon listing (all re-checked 2026-09-04). A gravity system's throughput is a batch rate that falls as the upper chamber empties, which the manual states explicitly, so there is no continuous gallons-per-minute service flow to record. No third-party measurement was substituted for the manufacturer's silence. |
| fit.roOutputGpd | The King Tank is a gravity filter with no membrane and no pump, so there is no reverse-osmosis output to publish; Waterdrop points TDS buyers to its separate RO range. |
| fit.roTankCapacity | The King Tank has no reverse-osmosis pressure tank. Its 2.25-gallon lower chamber is a gravity holding chamber and is recorded as the system capacity in the manual, not as an RO tank. |
| fit.pressureRange | The system is not connected to a pressurised line — the manual's only pressure discussion is that gravity head drops as the upper chamber empties. Neither the manual's specification table nor either product page publishes an operating pressure range. |
| fit.connectionSize | Nothing is plumbed in: the manual's parts list has a spigot and a hex nut fitted to the lower chamber, and no inlet or outlet connection to a water line, so no connection size is published. |
| cost.wasteRatio | There is no drain line and no reject stream. Waterdrop states the system produces 'no electricity or wastewater' and 'zero water loss', so a waste-to-product ratio does not exist to be measured. |
| install.estimatedHours | Waterdrop says only that the system 'installs in minutes' and gives no total time. The manual's own timings are per step (soak an element 60 seconds, flush the carbon element at least 60 seconds, flush a fluoride element at least 120 seconds, then flush the assembled system 2-3 times) and do not add up to a published install duration; a total was not invented from them. |
| seo.verification | The stage-5 verify loop has not run against this record yet; this field is stamped by that loop, not by research. |
Every source behind this page
- Brand officialaccessed: 2026-09-03https://www.waterdropfilter.com/products/wd-tank-king
- The brand's own product page shows 'In Stock—Estimated delivery in 3-5 business days' and an active Add to Cart for both King Tank styles.
- Specification table: 'Electricity Required: No'; capacity 2.25-gallon; food-grade stainless steel housing.
- 'No electricity or wastewater.'
- FAQ: 'This system is not designed to primarily reduce TDS… You can get a Waterdrop RO water filtration system if you want a filter system that does both.'
- Product FAQ: 'The filter media adopted in the King Tank portable water filter is natural coconut activated carbon, which effectively reduces chlorine and improves taste.'
- Product FAQ 'The TDS levels did not drop after filtration. Is this normal?': 'This system is not designed to primarily reduce TDS… You can get a Waterdrop RO water filtration system if you want a filter system that does both.'
- Product FAQ: 'To prevent overflow, it is recommended to empty the lower chamber completely prior to refilling the upper chamber.'
- Product FAQ: 'The two carbon filters can effectively filter up to 6,000 gallons of water. You need to replace the filter once it achieves the maximum filter capacity. The actual replacement time might vary according to the local water quality.'
- Specification table: 'Product Dimensions (In) 8.5*8.5*20.4'. The cylindrical body diameter is recorded as both width and depth.
- Specification table row 'Electricity Required: No'.
- 'It's spacious yet portable, easy to carry, and installs in minutes with no power or tools required.'
- 'The two carbon filters purify up to 6,000 gallons, while the two fluoride filters treat 1,000 gallons. No electricity or wastewater.' A system that produces no wastewater has nothing to drain.
- Product FAQ: 'King Tank water filter system can be easily set up and install all by yourself without prior plumbing experience.'
- The product page badges '1-Year Warranty'; the comparison table gives TK-F and TK-S a 1 Year warranty.
- Product page badges: 'Fast, Free Shipping', '30-Day Price Protection', '30-Day Worry-Free Returns', '1-Year Warranty'.
- Product FAQ 'Is the King Tank stainless steel water filter complicated to install?': 'King Tank water filter system can be easily set up and install all by yourself without prior plumbing experience.'
- The Specification table on Waterdrop's own King Tank product page carries the row 'Certification — NSF/ANSI 42 & 372', so the NSF/ANSI 42 assertion is made on waterdropfilter.com and not only in the Amazon copy. Re-opened live on 2026-09-04.
- The King Tank product page's specification table (Model, Product Dimensions, Product Weight, Certification, Capacity, Electricity Required) publishes no flow rate.
- Specification table: 'Electricity Required: No'; 'Product Dimensions (In) 8.5*8.5*20.4'.
- FAQ: 'King Tank water filter system can be easily set up and install all by yourself without prior plumbing experience.'
- Retailer listingaccessed: 2026-09-03https://www.amazon.com/dp/B09BC836BC
- Amazon shows the WD-TK as In Stock and sold by the Waterdrop Store.
- Brand bullet: the 2.25-gallon capacity is stated to meet 'water demands of a family of 4 people'.
- Model Number WD-TK, Model Name 'King Tank Series'.
- Waterdrop's own bullet on the exact-model listing: 'comes with a 2.25-gallon large capacity, thereby meeting water demands of a family of 4 people for pure water indoors and outdoors.'
- Amazon's price for the WD-TK (two black carbon elements, no stand) was $168.99, In Stock, on 2026-09-03.
- Waterdrop's own bullet frames the 6,000-gallon carbon capacity as 'saving you up to 45,000 plastic bottles (500ml) over three years', which is the manufacturer's own three-year usage basis for the annual figure.
- Amazon 'Customers say' summary across 1,469 ratings, with topic counts Quality (179), Water taste (125), Value for money (118), Build quality (24), Appearance (23).
- Verified-purchase review titled 'Higher quality stainless steel container than my Berkey' on the WD-TK listing: 'the stainless steel container is nicer quality and it is even prettier! The sight view water spigot is also better because of the little red dot that helps you see the water line with more ease'.
- Amazon 'Customers say' summary: 'opinions on leakage are divided, with some reporting no issues while others experience leaks'; Leakage is tagged on 22 reviews.
- Amazon 'Customers say' summary: 'The filtration system receives mixed feedback - while many say it provides clean water, one customer reports it doesn't filter out fluoride.'
- Waterdrop's Amazon bullet: 'This water filter system has passed authoritative NSF/ANSI 372 certification, and the black carbon filter is certified against NSF/ANSI 42 for the reduction of chlorine, taste and odor.'
- Waterdrop's own bullet frames the 6,000-gallon carbon capacity as 'saving you up to 45,000 plastic bottles (500ml) over three years'.
- Brand bullet: 'Please flush filter for 1 min before use, if faucet not fully compatible, splashing may occur but won't affect product.'
- The listing's specification table publishes no flow rate.
- WD-TK listing on 2026-09-04: price $168.99, In Stock, 4.5 out of 5 stars from 1,469 global ratings, capacity 2.25 gallons.
- 'Customers who viewed this item also viewed' on the same page lists 'Big Berkey 2.25 Gal Gravity Water Filter System with BB9-2 Filters', 4.5 out of 5 stars, 4,214 ratings, $367.00.
- Brand bullet: 'Please be aware that this system is not sourced by or sponsored by Berkey. Waterdrop is an independent brand.'
- Verified-purchase review titled 'Higher quality stainless steel container than my Berkey' (reviewed 2024-11-28) on the WD-TK listing: the reviewer bought a 2.25-gallon Big Berkey ten years earlier and writes of the Waterdrop that 'the stainless steel container is nicer quality and it is even prettier'.
- IAPMO listingaccessed: 2026-09-03https://myplc.iapmo.org/certificate#/19684
- IAPMO R&T file W-13936, issued to Qingdao Ecopure Filter Co. Ltd, carries a 'Gravity-Fed Water Filter System' product-type table whose Model Number column includes ECF-7088S, WD-TK-F, WD-TK-FS, WD-TK and WD-TK-S; the Brand Name cell reads Waterdrop against the four WD-TK models and is empty against ECF-7088S.
- The listing covers NSF/ANSI/CAN 372-2022 lead content of the materials and names no contaminant-reduction standard.
- The certificate states 'This IAPMO R&T Listing is current as of September 4, 2026' and the directory row shows status Active.
- IAPMO R&T file W-13936 names only NSF/ANSI/CAN 372-2022, Section 1417(d) of the Safe Drinking Water Act and the lead content requirements of Section 116875 of the California Health & Safety Code; no reduction standard appears on the certificate.
- The Model Number column of IAPMO R&T file W-13936, under Product Type 'Gravity-Fed Water Filter System', lists ECF-7088S, WD-TK-F, WD-TK-FS, WD-TK and WD-TK-S.
- The certificate names NSF/ANSI/CAN 372-2022 and the two lead-content legal requirements, and no reduction standard.
- IAPMO R&T file W-13936 lists WD-TK, WD-TK-F, WD-TK-FS and WD-TK-S as a Lead Free Water Filtration Product certified to NSF/ANSI/CAN 372-2022, with weighted average lead content <=0.25%.
- IAPMO R&T file W-13936 is issued to Qingdao Ecopure Filter Co. Ltd, 'NO. 13, YISHENGBAI ROAD ENVIRONMENTAL PROTECTION QINGDAO CHINA'; the pld.iapmo.org directory row for W-13936 shows the same Listee. Re-opened live on 2026-09-04.
- IAPMO R&T file W-13936 covers the King Tank models for NSF/ANSI 372 lead content and names no reduction standard.
- Manufacturer datasheetaccessed: 2026-09-03https://m.media-amazon.com/images/I/919zL+VUpKL.pdf
- King Tank user manual, p.5 and p.6: 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system.'
- Product Specifications table: system capacity 2.25 gallons, four system models WD-TK / WD-TK-F / WD-TK-S / WD-TK-FS.
- p.8 FAQ: the gravity-fed system filters out harmful substances while preserving beneficial minerals and does not reduce TDS.
- The manual's parts list and installation steps show a single carbon-element stage in the upper chamber, with the fluoride element as an optional attachment on WD-TK-F and WD-TK-FS only.
- King Tank user manual p.5 (Step 6) and p.6 (Operation and Use Tips, item 4): 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system.'
- Manual p.8 FAQ 'Why is the TDS value not reduced after filtration?': 'The gravity-fed water filter system filters out harmful substances while preserving beneficial minerals. If you are looking for water purifiers to reduce TDS, the RO water filtration system is the best option.'
- Manual p.8 certification footer: 'System Certified by IAPMO R&T against NSF/ANSI Standard 372 (<=0.25 lead).'
- Manual p.6 FAQ: 'There is not a water-tight seal between the upper and lower chambers of the system. Water can spill after the lower chamber is filled with water.'
- Manual p.2 parts table marks Fluoride Filter*2 as an excluded part on WD-TK and WD-TK-S and an included part on WD-TK-F and WD-TK-FS.
- Manual p.4 and p.5: 'Fluoride Filter* (Only applicable to WD-TK-F/WD-TK-FS)'.
- Manual p.8 note: 'The fluoride removal test is carried out under the standard conditions of a third-party laboratory, and actual results may vary.'
- Manual p.3 Product Specifications: 'Carbon Filter Capacity — Up to 6,000 gallons in total.'
- Manual p.3 Product Specifications: 'Fluoride Filter Capacity — Up to 1,000 gallons in total.'
- Manual p.3 Product Specifications: 'Operating Temperatures — 40-100 °F (4 - 37 °C)'.
- Manual p.8 Warranty: 'The product is not warranted against misuse, use in abnormal operation temperature conditions, conditions outside of the listed operating parameters…'
- King Tank user manual p.5 and p.6: 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system.'
- The manual's six installation steps are entirely manual assembly; no power connection appears in the parts list.
- The manual's six steps are consumer assembly with the supplied wrench; no plumbing, drain or electrical connection is described, so no professional install quote applies.
- Manual p.3: carbon filter capacity up to 6,000 gallons in total, fluoride filter capacity up to 1,000 gallons in total.
- Manual p.8 Warranty section, including the note 'This does not apply to any filter cartridge because the life expectancy varies depending on the quality of the incoming water.'
- The manual's whole installation is six steps: lid knob, spigot with the supplied wrench, flush the elements at a faucet, fit the elements, stack the chambers, flush the system 2-3 times.
- Manual p.2 parts list item 13 is a Wrench; Step 2 says to tighten the Spigot Hex Nut 'with an attached Wrench (13)'. No other tool appears in the manual.
- Waterdrop 'King Tank Gravity-Fed Water Filter System User Manual' (8 pages, V050), covering the four system models, the parts list, product specifications, six installation steps, operation, maintenance, FAQs and the warranty.
- Manual p.6 Maintenance: 'The whole system should be cleaned at least once a month'; 'Never put the filter in the freezer, and always re-flush it before using it again.'
- Manual p.6 Operation and Use Tips items 1 and 3.
- Manual p.5 (Step 6 note) and p.6 (Operation and Use Tips, item 4): 'Do not use with microbiologically unsafe or unknown quality water without adequate disinfection before or after the system.'
- Manual p.2 parts table: Fluoride Filter*2 is an excluded part on WD-TK and WD-TK-S, an included part on WD-TK-F and WD-TK-FS.
- Manual p.4/p.5: 'Fluoride Filter* (Only applicable to WD-TK-F/WD-TK-FS)'.
- Manual p.8: 'The fluoride removal test is carried out under the standard conditions of a third-party laboratory, and actual results may vary.'
- Manual p.8: 'The gravity-fed water filter system filters out harmful substances while preserving beneficial minerals. If you are looking for water purifiers to reduce TDS, the RO water filtration system is the best option.'
- Manual p.3 Product Specifications: carbon filter capacity up to 6,000 gallons in total; fluoride filter capacity up to 1,000 gallons in total.
- Manual p.6 FAQ: 'It is normal for one to two inches of water to remain in the upper chamber. Because this system is gravity-fed, as the water level in the upper chamber drops, the filtering process naturally slows down because there is less water pressure available to force water through the elements.'
- The manual's Product Specifications table publishes a system capacity of 2.25 gallons and no flow rate.
- Manual p.3-p.5: six installation steps, the only tool being the supplied wrench; no plumbing, drain or power connection.
- Manual p.8 back page: 'Made in China V050 — Qingdao Ecopure Filter Co., Ltd.'
- NSF listingaccessed: 2026-09-04https://info.nsf.org/Certified/DWTU/Listings.asp?TradeName=WD-TK&Standard=&ProductType=&PlantState=&PlantCountry=&PlantRegion=&hdModlStd=ModlStd
- NSF's Drinking Water Treatment Units directory returns 'No Matching Products Found' for trade name WD-TK on 2026-09-04; a control search on the same form returned 18 listed products under trade name ECF-7008S — all from manufacturer Qingdao Ecopure Filter Co., Ltd., 4 of them Waterdrop-branded — so the form was executing.
- NSF's DWTU directory returned 'No Matching Products Found' for WD-TK on 2026-09-04.
- WQA listingaccessed: 2026-09-04https://find.wqa.org/find-products#/keyword/WD-TK
- WQA's certified product listings return 'No results.' for WD-TK on 2026-09-04; a control search for Brita on the same form returned NSF/ANSI 42, 53 and 401 listings.
- WQA's certified product listings returned 'No results.' for WD-TK, King Tank and Waterdrop on 2026-09-03; control searches for Brita and Ecopure returned results on the same run.
- WQA's certified product listings returned 'No results.' for WD-TK on 2026-09-04.
- Brand officialaccessed: 2026-09-03https://www.waterdropfilter.com/products/bb9-2-black-purification-elements-replacement-water-filter
- The WD-BB9 black element page states the filter 'adopts natural coconut shell activated carbon to reduce chlorine, sediment, rust and odor in water'.
- A 2-pack of WD-BB9 black carbon elements is $78.99 direct from Waterdrop (a 4-pack is $111.99).
- The element page names the King Tank TK-F and TK-S as the systems it fits.
- WD-BB9 black element pricing on 2026-09-03: 2 Pack $78.99 ($39.49 each), 4 Pack $111.99 ($27.99 each).
- Brand officialaccessed: 2026-09-03https://www.waterdropfilter.com/products/waterdrop-7990-gravity-water-filter
- Replacement set page: 'carbon filters last for 6,000 gallons (1 pair); Fluoride filters last for 1,000 gallons (1 pair)'.
- Replacement element set page: 'Effective filtration: reduces chlorine, fluoride, odors, and sediments to give you cleaner, smoother, better-tasting water'.
- Combined black plus fluoride element set priced at $94.99 on 2026-09-03.
- Brand officialaccessed: 2026-09-04https://www.waterdropfilter.com/products/wd-tank-king-f-s
- The With Stand page publishes the same 8.5*8.5*20.4 in dimensions and 10.9 lb weight for TK-S.
- 'Save money and reduce waste with zero water loss and no electricity cost.'
- Brand officialaccessed: 2026-09-04https://www.waterdropfilter.com/products/wd-tank-king.js
- Waterdrop's own storefront product JSON gives SKU WD-TK a price of 22999 cents with compare_at_price null, i.e. $229.99 is the regular list price rather than a discounted one.
- The other three SKUs list at $259.99 (WD-TK-F-D), $269.99 (WD-TK-S) and $299.99 (WD-TK-FS).
- Brand officialaccessed: 2026-09-04https://www.waterdropfilter.com/products/replacement-for-gravity-fed-filtration-systems-pf-2
- A 2-pack of white fluoride elements for King Tank systems is $56.99 direct from Waterdrop, shown as Sold Out on 2026-09-03.
- Brand officialaccessed: 2026-09-03https://www.youtube.com/watch?v=sFuWMmShyas
- Waterdrop's own installation video, 'How to Install Waterdrop King Tank Gravity-Fed Water Filter System WD-TK | Installation Guide', 2:36, on the Waterdrop Filter channel.
- Reddit threadaccessed: 2026-09-03https://www.reddit.com/r/OffGrid/comments/14y0qji/waterdrop_gravity_fed_king_tank/
- r/OffGrid thread 'Waterdrop Gravity Fed - King Tank', re-read rendered in a browser on 2026-09-04; the original post (by the thread's author) links Amazon ASIN B09BC836BC, and a different user comments that they own that exact filter system.
- r/OffGrid 'Waterdrop Gravity Fed - King Tank': the original poster asks whether the King Tank can make river water drinkable without boiling, and a commenter answers that it will remove heavy metals but is not rated for bacteria or virus treatment and should be used together with boiling.
- r/OffGrid 'Waterdrop Gravity Fed - King Tank', re-read rendered in a browser on 2026-09-04: a commenter who reports owning that exact system writes 'Every bit as good as the berkey, and the sight glass and metal spigot are included.' The commenter never states owning or having used a Berkey.
- Retailer listingaccessed: 2026-09-03https://www.google.com/search?q=waterdrop+king+tank
- Google's product panel for 'Waterdrop King Tank Gravity-Fed Water Filter, 2.25-Gallon Stainless Steel System, Includes Stand and 4 Filters' (4.6 from 39 reviews) surfaces a 3-star review, marked 'Reviewed on waterdropfilter.com', reading: 'Quality manufacturing but filtering process takes too long. Also, the rubber feet on the bottom of the stand come off every time you move the unit.'
- Reddit threadaccessed: 2026-09-03https://www.reddit.com/r/WaterTreatment/comments/1k6utcn/for_those_that_have_the_stainless_gravity_tanks/
- r/WaterTreatment thread 'For those that have the stainless gravity tanks… what did you get and why?', opened and read in a browser on 2026-09-03. The renter who opened it names the WaterDrop King Tank among Berkey and ProOne and says the certifications are what interested them; a commenter replies that gravity-fed filters are overpriced.
- Government agencyaccessed: 2026-09-04https://www.saferproducts.gov/RestWebServices/Recall?RecallTitle=Waterdrop&format=json
- The CPSC recall API returned an empty result set for RecallTitle, RecallDescription, ProductName and Manufacturer = Waterdrop on 2026-09-03. A control query (ProductName = 'water filter') returned two recalls on the same run, so the endpoint was answering.
- No recall covering the King Tank, Qingdao Ecopure Filter Co. Ltd or the WD-TK models was found.
- Government agencyaccessed: 2026-09-04https://www.bing.com/search?q=Waterdrop+%22King+Tank%22+lawsuit+OR+recall+OR+litigation+water+filter
- A news and web search for Waterdrop 'King Tank' lawsuit / recall / litigation returned no litigation or recall coverage on 2026-09-03; the results were brand and retailer pages only.
- NSF listingaccessed: 2026-09-04https://info.nsf.org/Certified/DWTU/Listings.asp?TradeName=WD-BB9&Standard=&ProductType=&PlantState=&PlantCountry=&PlantRegion=&hdModlStd=ModlStd
- NSF's Drinking Water Treatment Units directory returns 'No Matching Products Found' for trade name WD-BB9 on 2026-09-03; a control search for ECF-7008S on the same form returned results, so the search executed.
- IAPMO listingaccessed: 2026-09-04https://pld.iapmo.org/
- IAPMO R&T's Product Listing Directory returned 'No data found' for Listed Model searches of WD-BB9 and BB9-2 on 2026-09-03; a control search of Listee Name 'Ecopure' returned 16 files on the same run.
- NSF listingaccessed: 2026-09-04https://info.nsf.org/Certified/dwtu/listings.asp?CompanyName=Qingdao+Ecopure&Program=DWTU
- NSF lists Qingdao Ecopure Filter Co., Ltd. under NSF/ANSI 42, NSF/ANSI 53 and NSF/ANSI 401 for other products; no King Tank or WD-TK model appears anywhere in that listing.
Cite this page
TapWaterData Editorial. "Waterdrop King Tank Review: Specs, Cost & Cert Check." TapWaterData, verified 2026-09-03. https://www.tapwaterdata.com/filters/brand/waterdrop/king-tank
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