SG13 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.
SG13 tap water quality report · 2026
Hardness
Very hard
Hertford (supply zone) · read on 29 September 2026
Details
Hertford (supply zone) · read on 29 September 2026
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
7 overflows within 10 km of SG13 centre
75 spills in 2025
Details
75 spills in 2025
Lead pipes
47% built before 1973
Estimate, not a test. Homes in the parts of SG13 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: 46–48%. England and Wales: 61% (2026).
Details
Estimate, not a test. Homes in the parts of SG13 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: 46–48%. England and Wales: 61% (2026).
Who supplies water in SG13
Supplies 461 of 531 postcodes (87%)
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.
Supplies 69 of 531 postcodes (13%)
Thames Water's phone number isn't in our records; their contact page lists it.
Sewerage: Usually Thames Water — they provide water and sewerage across most of their area. Your water bill confirms yours.
Boundary or unplaced: 1 postcodes
Drinking-water test record
Affinity Water: 461 of 531 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
Thames Water: 69 of 531 postcodes
Thames Water
Thames Water, company-wide
- Regulator
- DWI
- Report year
- 2025
- Failed tests
- Not shown
- Tests
- 436,206
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: 8 |
| Iron | Failed tests: 6 |
| Lead | Failed tests: 13 |
| Nickel | Failed tests: 20 |
| Nitrite – consumers taps | Failed tests: 4 |
| Total coliforms (confirmed) | Failed tests: 13 |
| Turbidity – indicator | 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 SG13?
71% of SG13's postcodes are in the Hertford supply zone (Affinity Water): 316 mg/l, very hard.
Hertford · Affinity Water (379 of 531 postcodes)
316 mg/l · 22.2 °Clark · 17.7 °dH · 31.6 °fH
From the company's postcode lookup.
Hertford (supply zone) · read on 29 September 2026
Source: Affinity Water — read 29 September 2026
2 identified supply zones in SG13
Hertford · Affinity Water (379 of 531 postcodes)
316 mg/l · 22.2 °Clark · 17.7 °dH · 31.6 °fH
From the company's postcode lookup.
Hertford (supply zone) · read on 29 September 2026
Source: Affinity Water — read 29 September 2026
Hatfield/Potters Bar · Affinity Water (82 of 531 postcodes)
279 mg/l · 19.6 °Clark · 15.6 °dH · 27.9 °fH
From the company's postcode lookup.
Hatfield/Potters Bar (supply zone) · read on 29 September 2026
Source: Affinity Water — read 29 September 2026
69 postcodes without an identified supply zone
Thames Water (69 of 531 postcodes)
“all the water in our region is hard”
Thames Water, company-wide · read on 26 September 2026
Source: Thames Water — dated 26 September 2026, read 26 September 2026
Storm overflows nearby
7 overflows within 10 km of SG13 centre · 75 spills in 2025
SG13 (district) · 2025
Source: Environment Agency EDM annual return 2025 — dated 20 August 2026, read 13 October 2026
Overflows here are run by Thames Water.
2 of these were monitored for only part of 2025.
Nearest 5 shown
BRICKENDON WWTW
Into HARMONDS BROOK WEST ARM · 3.3 km from the centre of SG13
46 spills · 518 hours · Monitored 100% of 2025
Chapmore End
Into Rib · 5.1 km from the centre of SG13
7 spills · 9.8 hours · Monitored 100% of 2025
Essendon, Holywell Bridge
Into Lea · 5.8 km from the centre of SG13
0 spills · 0 hours · Monitored 100% of 2025
RYE MEADS WWTW
Into TOLL HOUSE STREAM · 6.5 km from the centre of SG13
5 spills · 38.3 hours · Monitored 99.9% of 2025
West End, Essendon
Into Wood Hill Brook · 7 km from the centre of SG13
0 spills · 0 hours · Monitored 100% 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
47% built before 1973
47% of homes here were built before 1973 — estimate, not a test.
Homes in the parts of SG13 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: 46–48%. England and Wales: 61% (2026).
Older homes are more likely to have lead pipes. Only a test tells you whether yours does.
SG13 (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 SG13
- Is the water in SG13 hard or soft?
- Affinity Water: very hard, 316 mg/l, 22.2 °Clark, 17.7 °dH, 31.6 °fH (Hertford (supply zone), read on 29 September 2026). From the company's postcode lookup. Affinity Water: hard, 279 mg/l, 19.6 °Clark, 15.6 °dH, 27.9 °fH (Hatfield/Potters Bar (supply zone), read on 29 September 2026). From the company's postcode lookup. Thames Water: “all the water in our region is hard” (Thames Water, Thames Water, company-wide, read on 26 September 2026).
- What does the drinking water regulator's record show for SG13?
- 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 SG13 have lead pipes?
- 47% of homes here were built before 1973 — estimate, not a test. Homes in the parts of SG13 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: 46–48%. 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 SG13 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 ↗ · read on 29 September 2026 · read 29 September 2026
- Thames Water ↗ · read on 26 September 2026 · read 26 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, Thames Water: Database right, used under the publisher's terms.
Water company boundaries © Water UK, licensed under CC BY 4.0Contains public sector information licensed under the Open Government Licence v3.0All content is available under the Open Government Licence v3.0, except where otherwise stated © Crown copyright
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