CM23 tap water: what's in it?
Affinity Water: at least 20 tests failed UK drinking-water standards in 2025 (DWI, company-wide).
Some published DWI figures don't reconcile or identify a company, so we've left them out; the true number may be higher. England overall: 99.97% of tests met standards.
CM23 tap water quality report · 2026
Hardness
Very hard
Bishop Stortford (supply zone) · 1 January 2025 to 31 December 2025
Details
Bishop Stortford (supply zone) · 1 January 2025 to 31 December 2025
Hosepipe ban
In force in part of Affinity Water's area
A ban has been reported, but the notice doesn't confirm which parts of the supply area it covers. Check with your water company before using a hosepipe. Checked 11 October 2026 at 02:34
Details
A ban has been reported, but the notice doesn't confirm which parts of the supply area it covers. Check with your water company before using a hosepipe. Checked 11 October 2026 at 02:34
Storm overflows
14 overflows within 10 km of CM23 centre
145 spills in 2025
Details
145 spills in 2025
Lead pipes
37% built before 1973
Estimate, not a test. Homes in the parts of CM23 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 37–38%. England and Wales: 61% (2026).
Details
Estimate, not a test. Homes in the parts of CM23 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 37–38%. England and Wales: 61% (2026).
Who supplies water in CM23
Supplies 1,100 of 1,193 postcodes (92%)
Affinity Water's phone number isn't in our records; their contact page lists it.
We can't tell your sewerage company from official data for this area. It's named on your water bill.
Boundary or unplaced: 93 postcodes
Drinking-water test record
Affinity Water: 1,100 of 1,193 postcodes
Affinity Water
Affinity Water, company-wide
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- 189,963
The regulator's published total and its company rows disagree, so we don't show a count.
| Parameter | Failed tests |
|---|---|
| E. coli (confirmed) | Failed tests: 4 |
| Enterococci (confirmed) | Failed tests: 2 |
| Iron | Failed tests: 1 |
| Lead | Failed tests: 6 |
| Nickel | Failed tests: 3 |
| Total coliforms (confirmed) | Failed tests: 4 |
Source: DWI england 2025, Annex B — dated 6 July 2026, read 13 October 2026
Source: DWI england 2025, Annex A — dated 6 July 2026, read 13 October 2026
England: 99.97% of tests met standards in 2025 (DWI).
Source: DWI england 2025, national compliance — dated 6 July 2026, read 13 October 2026
How hard is the water in CM23?
82% of CM23's postcodes are in the Bishop Stortford supply zone (Affinity Water): 345 mg/l, very hard.
Bishop Stortford · Affinity Water (974 of 1,193 postcodes)
345 mg/l · 24.2 °Clark · 19.3 °dH · 34.5 °fH
Zone average.
Bishop Stortford (supply zone) · 1 January 2025 to 31 December 2025
Source: Affinity Water — dated 1 January 2025 to 31 December 2025, read 29 September 2026
5 identified supply zones in CM23
Bishop Stortford · Affinity Water (974 of 1,193 postcodes)
345 mg/l · 24.2 °Clark · 19.3 °dH · 34.5 °fH
Zone average.
Bishop Stortford (supply zone) · 1 January 2025 to 31 December 2025
Source: Affinity Water — dated 1 January 2025 to 31 December 2025, read 29 September 2026
Stansted · Affinity Water (98 of 1,193 postcodes)
346 mg/l · 24.3 °Clark · 19.4 °dH · 34.6 °fH
From the company's postcode lookup.
Stansted (supply zone) · read on 28 September 2026
Source: Affinity Water — read 28 September 2026
Harlow North · Affinity Water (13 of 1,193 postcodes)
329 mg/l · 23.1 °Clark · 18.4 °dH · 32.9 °fH
From the company's postcode lookup.
Harlow North (supply zone) · read on 29 September 2026
Source: Affinity Water — read 29 September 2026
Sawbridgeworth · Affinity Water (9 of 1,193 postcodes)
339 mg/l · 23.8 °Clark · 19.0 °dH · 33.9 °fH
From the company's postcode lookup.
Sawbridgeworth (supply zone) · read on 29 September 2026
Source: Affinity Water — read 29 September 2026
Standon · Affinity Water (1 of 1,193 postcodes)
330 mg/l · 23.2 °Clark · 18.5 °dH · 33.0 °fH
Zone average.
Standon (supply zone) · 1 January 2025 to 31 December 2025
Source: Affinity Water — dated 1 January 2025 to 31 December 2025, read 29 September 2026
5 postcodes without an identified supply zone
Affinity Water (5 of 1,193 postcodes)
We do not have a verified hardness figure for this area. Ask your water company for its water quality report.
Storm overflows nearby
14 overflows within 10 km of CM23 centre · 145 spills in 2025
CM23 (district) · 2025
Source: Environment Agency EDM annual return 2025 — dated 20 August 2026, read 13 October 2026
Overflows here are run by Thames Water.
11 of these were monitored for only part of 2025.
Nearest 5 shown
BISHOP'S STORTFORD MAIN SPS
Into STORT NAVIGATION · 1.6 km from the centre of CM23
1 spill · 1.4 hours · Monitored 99.9% of 2025
Birchanger - Duck End
Into Great Hallingbury Brook · 2.8 km from the centre of CM23
0 spills · 0 hours · Monitored 99.7% of 2025
STANSTED MOUNTFITCHET WWTW
Into THE RIVER STORT · 3.1 km from the centre of CM23
28 spills · 313 hours · Monitored 99% of 2025
LITTLE HALLINGBURY WWTW
Into LITTLE HALLINGBURY BROOK · 4.2 km from the centre of CM23
26 spills · 209.3 hours · Monitored 100% of 2025
Stansted Airport
Into Pincey Brook · 6.2 km from the centre of CM23
1 spill · 3.9 hours · Monitored 99.4% of 2025
Annual 2025 figures from monitored overflows. Not live, and not a bathing-water or tap-water verdict.
- 57 England outfalls in the 2025 return had no usable location and aren't counted.
- Northern Ireland isn't covered: No licensed annual per-outfall source in the approved source list; BT postcode coordinates require an LPS licence.
Older homes and lead pipes
37% built before 1973
37% of homes here were built before 1973 — estimate, not a test.
Homes in the parts of CM23 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 37–38%. England and Wales: 61% (2026).
Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
CM23 (district) · 2026
Source: Valuation Office Agency, Council Tax: stock of properties — dated 31 March 2026, read 24 September 2026
Fluoride
We cannot confirm whether this area is part of a water fluoridation scheme. Ask your water supplier using your postcode.
Around one in ten people in England receive drinking water supplied by a fluoridation scheme.
England · 2026 health monitoring report
Source: UKHSA and DHSC — dated 30 March 2026, read 13 October 2026
Hosepipe bans
What you can do
As an Amazon Associate we earn from qualifying purchases. Links go to amazon.com; Amazon's Earn Globally service can localise them to amazon.co.uk. Check the model and UK delivery before buying.
Water filter jugs
LifeStraw
LSH7GLSPK21
Performance certification:
Certified by WQA to NSF/ANSI 42 for Aesthetic Chlorine and Taste and Odor; Certified by WQA to NSF/ANSI 53 for Lead and Mercury; Certified by WQA to NSF/ANSI 401 for Microplastics (a US/international standard; it is not UK approval)
View Detailsreduces chlorine taste and odour in drinking water.
A UK retailer lists this model. Amazon UK stock and delivery are unverified; this Amazon link may not ship to the UK. Check the exact model and UK delivery before you pay.
UK availability evidence checked 14 October 2026.
Shower filters
Weddell Water
WD-100BL
Performance certification:
Certified by NSF to NSF/ANSI 177 for Free Available Chlorine Reduction (a US/international standard; it is not UK approval)
View Detailsreduces chlorine in shower water; does not soften water.
A UK retailer lists this model. Amazon UK stock and delivery are unverified; this Amazon link may not ship to the UK. Check the exact model and UK delivery before you pay.
Check it fits your shower fitting before buying; a US fitting may need an adaptor.
UK availability evidence checked 14 October 2026.
We haven't verified a water softener for UK buyers yet.
What a pick has to pass:
- An exact-model listing from NSF, WQA or IAPMO for the model sold in the UK
- Listed to NSF/ANSI 44, the water softener standard
- The manufacturer's documented feed connection and water-pressure range, so a plumber can check them against UK pipework
- UK availability evidenced by Amazon UK, the manufacturer or a UK retailer, checked in the last 90 days
Until we can recommend one, see what a softener costs to buy, fit and run in the UK. Water softener cost
We haven't verified a lead test kit for UK buyers yet.
What a pick has to pass:
- A lead result reported by a laboratory accredited for that test (UKAS, ISO/IEC 17025), named on the kit's listing
- UK availability evidenced by Amazon UK, the manufacturer or a UK retailer, checked in the last 90 days
Start with your water company: if you think you have lead pipes, you can ask it to test the water at your kitchen tap. Which water test you need
Common water problems
How much does a water softener cost in the UK?
Water softener cost UK 2026: price by home size
Why is my tap water cloudy or white?
Why is my tap water cloudy or white? (UK)
Brown tap water: causes and what to do (UK)
Why does my tap water taste metallic?
Tap water tastes metallic? Causes and fixes (UK)
Questions about tap water in CM23
- Is the water in CM23 hard or soft?
- Affinity Water: very hard, 345 mg/l, 24.2 °Clark, 19.3 °dH, 34.5 °fH (Bishop Stortford (supply zone), 1 January 2025 to 31 December 2025). Zone average. Affinity Water: very hard, 346 mg/l, 24.3 °Clark, 19.4 °dH, 34.6 °fH (Stansted (supply zone), read on 28 September 2026). From the company's postcode lookup. Affinity Water: very hard, 329 mg/l, 23.1 °Clark, 18.4 °dH, 32.9 °fH (Harlow North (supply zone), read on 29 September 2026). From the company's postcode lookup. Affinity Water: very hard, 339 mg/l, 23.8 °Clark, 19.0 °dH, 33.9 °fH (Sawbridgeworth (supply zone), read on 29 September 2026). From the company's postcode lookup. Affinity Water: We do not have a verified hardness figure for this area. Ask your water company for its water quality report. Affinity Water: very hard, 330 mg/l, 23.2 °Clark, 18.5 °dH, 33.0 °fH (Standon (supply zone), 1 January 2025 to 31 December 2025). Zone average.
- What does the drinking water regulator's record show for CM23?
- Affinity Water: at least 20 tests failed UK drinking-water standards in 2025 (DWI, company-wide). Some published DWI figures don't reconcile or identify a company, so we've left them out; the true number may be higher. England overall: 99.97% of tests met standards.
- Could homes in CM23 have lead pipes?
- 37% of homes here were built before 1973 — estimate, not a test. Homes in the parts of CM23 we can match to council-tax records (100% of its postcodes) whose build period is known; the share with no recorded build period isn't published for these areas. Allowing for suppressed counts: 37–38%. England and Wales: 61% (2026). Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
- Is the water in CM23 fluoridated?
- We cannot confirm whether this area is part of a water fluoridation scheme. Ask your water supplier using your postcode. Around one in ten people in England receive drinking water supplied by a fluoridation scheme.
Sources and method
- Water Company Boundaries (UC2) ↗ · 19 September 2026 · read 20 September 2026
- DWI england 2025, Annex B ↗ · 2025 · read 13 October 2026
- DWI england 2025, national compliance ↗ · 2025 · read 13 October 2026
- Affinity Water ↗ · 1 January 2025 to 31 December 2025 · read 29 September 2026
- Affinity Water ↗ · read on 28 September 2026 · read 28 September 2026
- Affinity Water ↗ · read on 29 September 2026 · read 29 September 2026
- Environment Agency EDM annual return 2025 ↗ · 2025 · read 13 October 2026
- Valuation Office Agency, Council Tax: stock of properties ↗ · 2026 · read 24 September 2026
- UKHSA and DHSC ↗ · 2026 health monitoring report · read 13 October 2026
- Environment Agency ↗ · 11 October 2026 · read 11 October 2026
Affinity Water, Affinity Water, Affinity Water, Affinity Water, Affinity Water: Database right, used under the publisher's terms.
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