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tapwater
England and Wales average 9.0

Tap water in SG8, North HertfordshireNitrite is over the limit.Very hard.

Supplied by Affinity Water. 419 samples, 24 substances, latest on 9 December 2025. Nitrite came in above the legal limit. Everything else passed.

Get softener quotes for SG8See everything that was tested

8.8 / 10

The tank is as full as the score. The specks are the minerals that make water hard.

What to do about it

Hard water: compare softener quotes

At 273 mg/L a softener is the only thing that stops limescale. Filters do not soften water.

It pays for itself in most homes at this hardness, through a boiler that stays efficient and appliances that last.

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What's in a glass of SG8 water

Every bubble is a substance the lab measured. The higher it floats, the closer it came to its legal limit, the dashed line at the top.

Nitrite is over its legal limit, at 144% of it.

0%25%50%75%limitLegal limitManganese: 0.000363 mg/L, <1% of the 0.05 mg/L limitManganese<1%Chromium: 0.000383 mg/L, <1% of the 0.05 mg/L limitChromium<1%Aluminium: 0.00199 mg/L, <1% of the 0.2 mg/L limitAluminium<1%Cadmium: 0.000054 mg/L, 1% of the 0.005 mg/L limitCadmium1%Copper: 0.029 mg/L, 1% of the 2 mg/L limitCopper1%Arsenic: 0.00017 mg/L, 2% of the 0.01 mg/L limitArsenic2%Antimony: 0.000098 mg/L, 2% of the 0.005 mg/L limitAntimony2%Selenium: 0.000882 mg/L, 2% of the 0.04 mg/L limitSelenium2%Mercury: 0.000023 mg/L, 2% of the 0.001 mg/L limitMercury2%Turbidity: 0.1 NTU, 3% of the 4 NTU limitTurbidity3%Trihalomethanes: 0.00396 mg/L, 4% of the 0.1 mg/L limitTrihalomethanes4%Iron: 0.00897 mg/L, 4% of the 0.2 mg/L limitIron4%Boron: 0.046 mg/L, 5% of the 1 mg/L limitBoron5%Lead: 0.000673 mg/L, 7% of the 0.01 mg/L limitLead7%Colour: 2 mg/L Pt/Co, 10% of the 20 mg/L Pt/Co limitColour10%Nickel: 0.00205 mg/L, 10% of the 0.02 mg/L limitNickel10%Fluoride: 0.176 mg/L, 12% of the 1.5 mg/L limitFluoride12%Ammonia: 0.06 mg/L, 12% of the 0.5 mg/L limitAmmonia12%Bromate: 0.00147 mg/L, 15% of the 0.01 mg/L limitBromate15%Nitrate: 35.9 mg/L, 72% of the 50 mg/L limitNitrate72%Nitrite: 0.718 mg/L, 144% of the 0.5 mg/L limitNitrite144%
  1. Nitrite144%
  2. Nitrate72%
  3. Bromate15%
  4. Ammonia12%
  5. Fluoride12%
  6. Nickel10%
  7. Colour10%
  8. Lead7%
  9. Boron5%
  10. Iron4%
  11. Trihalomethanes4%
  12. Turbidity3%
  13. Mercury2%
  14. Selenium2%
  15. Antimony2%
  16. Arsenic2%
  17. Copper1%
  18. Cadmium1%
  19. Aluminium<1%
  20. Chromium<1%
  21. Manganese<1%
  • E. coli none found
  • Coliform Bacteria none found
  • Conductivity 514 µS/cm
All 24 results as a table
SubstanceResultLegal limitShare of limit
Nitrite0.718 mg/L0.5 mg/L
144%
E. coli0 count/100mlMust be zeroNone found
Turbidity0.1 NTU4 NTU
3%
Coliform Bacteria0 count/100mlMust be zeroNone found
Copper0.029 mg/L2 mg/L
1%
Manganese0.000363 mg/L0.05 mg/L
<1%
Colour2 mg/L Pt/Co20 mg/L Pt/Co
10%
Arsenic0.00017 mg/L0.01 mg/L
2%
Conductivity514 µS/cmNo legal limit–
Antimony0.000098 mg/L0.005 mg/L
2%
Fluoride0.176 mg/L1.5 mg/L
12%
Trihalomethanes0.00396 mg/L0.1 mg/L
4%
Bromate0.00147 mg/L0.01 mg/L
15%
Cadmium0.000054 mg/L0.005 mg/L
1%
Chromium0.000383 mg/L0.05 mg/L
<1%
Mercury0.000023 mg/L0.001 mg/L
2%
Nickel0.00205 mg/L0.02 mg/L
10%
Nitrate35.9 mg/L50 mg/L
72%
Aluminium0.00199 mg/L0.2 mg/L
<1%
Boron0.046 mg/L1 mg/L
5%
Selenium0.000882 mg/L0.04 mg/L
2%
Iron0.00897 mg/L0.2 mg/L
4%
Ammonia0.06 mg/L0.5 mg/L
12%
Lead0.000673 mg/L0.01 mg/L
7%

273mg of limescale minerals in every litre

This is the water that furs up kettles

Very hard on the UK scale. It is fine to drink. It is hard on boilers, showers, skin and anything that heats water, and a jug or tap filter will not change that.

Soft400 mg/L

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Outside your tap

Your river is the Mel, rated moderate

The Environment Agency rated the Mel as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by fish. It fails the chemical test, as every river, estuary and stretch of coast in England does, because of long-lasting pollutants such as mercury, PFOS (a forever chemical) and old flame retardants.

None of this is a test of your tap water. Environment Agency record · River health across England

Within 10 km

3

forever-chemical detections in nearby rivers and groundwater

At 1 site. The highest was PFOA at 0.0059 µg/L, at Fowlmere Rspb Reserve, Watercress, Hut Springs, 5.1 km away, in April 2025. These are river and borehole samples, not tests of your tap water.

Every PFAS sample around Cambridge · Which filters remove PFAS · PFAS explained

SG8 in short

Tap water in SG8 (North Hertfordshire) is supplied by Affinity Water in the North Hertfordshire Central zone and scores 8.8 out of 10, against an England and Wales average of 9.0. 1 of 24 tested substances was close to or over a limit. The latest sample is from 9 December 2025.

  • Nitrite was measured at 0.72 mg/L, 44% over the UK limitIt is the only one of 24 tested substances to go over its limit. See the full results
  • The lowest score of the 6 areas tested in North HertfordshireSG8 scores 8.8 out of 10. The best in North Hertfordshire, SG6, scores 9.3.
  • Every one of the 5 neighbouring districts scores higherSG6 next door scores 9.3, against 8.8 here. Supply zones, not distance, explain the gap. See SG6

Next door

SG39.1 out of 10 · 296 mg/LSG69.3 out of 10 · 294 mg/LSG58.9 out of 10 · 368 mg/LSG79.3 out of 10 · 323 mg/LSG48.9 out of 10 · 368 mg/L

Questions about SG8 water

Is SG8 tap water safe to drink?

Based on the latest tests, SG8 (North Hertfordshire) water scores 8.8/10, which is safe. 1 of 24 tested contaminants exceeded recommended levels. Water is supplied by Affinity Water.

What contaminants are in SG8 water?

We tested 24 contaminants in SG8 water. 1 were flagged, including Nitrite. PFAS (forever chemicals) were also measured in rivers and groundwater within 10 km, though not in the tap-water tests themselves.

Who supplies water in SG8?

SG8 (North Hertfordshire) is supplied by Affinity Water. You can view their full profile and compliance data on our supplier page.

Is SG8 water hard or soft?

Water in SG8 (North Hertfordshire) has a hardness of 273 mg/L CaCO3, which is classified as very hard. Hard water can cause limescale buildup. A water softener or filter jug may help.

Should I use a water filter in SG8?

With 1 contaminant above recommended levels in SG8, a water filter could help. A reverse osmosis or activated carbon filter is recommended for PFAS removal. See our filter recommendations for your area.

Are there PFAS forever chemicals in SG8 water?

The tap-water tests we hold for SG8 do not include a PFAS result. Environment Agency monitoring found PFAS in 3 river and groundwater samples from 1 sites within 10 km of SG8, the highest being PFOA at 0.0059 µg/L about 5.1 km away. These are environmental samples, not tests of tap water. The UK currently has no legal limit for PFAS in drinking water; the Drinking Water Inspectorate uses a 0.1 µg/L guideline for individual compounds. Reverse osmosis filters can reduce PFAS levels.

How clean is the river near SG8?

The Environment Agency rated the Mel as moderate for ecological health in its 2025 assessment, meaning the river is noticeably changed by pollution or engineering. It is held back by fish. It fails the chemical test, as every river, estuary and stretch of coast in England does, because of long-lasting pollutants such as mercury, PFOS (a forever chemical) and old flame retardants. This is a rating of the river, not of tap water in SG8, which is treated before it reaches homes.

Keep reading

PFAS explainedNitrate levelsHow to test your waterBest water filtersFilter shower headsWater testing kitsUK water rankingsWater hardness checkerWater hardness map

River and groundwater readings near SG8

Environment Agency samples from rivers, groundwater and reservoirs nearby. Not your tap water. For scale they are shown against drinking water limits; rivers are judged against much stricter environmental standards, and on those every river in England fails for chemicals.

SubstanceReadingDrinking water limit
pH7.83 pHNone
Temperature18.8 °CNone
Conductivity840 µS/cmNone
Ammonia0.032 mg/L0.5 mg/L
Nitrate11 mg/L50 mg/L
Nitrite0.033 mg/L0.5 mg/L
Dissolved Oxygen8.46 mg/LNone
Phosphate0.6 mg/LNone

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Source: Affinity Water test results, published through the Stream Water Data Portal; rivers and PFAS from the Environment Agency. Page updated . How we score · Where the data comes from