264mg of limescale minerals in every litre, the median across HA districts
Is Harrow a hard water area?
Yes. Tap water across the HA postcode area is very hard, the top band on the scale water companies use, with a median of 264 mg/L calcium carbonate. It ranges from 256 mg/L in HA8 to 271 mg/L in HA1, from 10 districts with their own water company reading.
- Soft
- 0 to 60 mg/L
- Moderately soft
- 60 to 120 mg/L
- Slightly hard
- 120 to 180 mg/L
- Hard
- 180 to 200 mg/L
- Very hard
- 200 to 400 mg/L
Hardness by HA district
Hardest first. Hard starts at 180 mg/L, very hard at 250.
What to do about it
Hard water: compare softener quotes
At 264 mg/L most HA homes get their money back on a softener within a few years. A filter will not touch limescale; only a softener does.
- Free quotes
- Local installers
- No obligation
Check your own district first
The area figure is a median. Your district can sit anywhere between 256 and 271 mg/L.
Softener quotes for Harrow
At 264 mg/L most HA homes get their money back on a softener within a few years. Free quotes from installers covering your postcode.
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Before you buy
- Do I need a water softener?The hardness bands, the symptoms, and when the answer is no
- Best water softener UKHarvey, Kinetico, BWT, Monarch and Water2Buy compared
- Water softener costUnit, fitting and salt, and how long the payback takes
- Installation explainedWhere it goes, the bypass tap, the drain, DIY or plumber
- Harvey vs KineticoThe two premium twin-cylinder brands, side by side
- Softener salt guideTablet, block or granular, and how much you get through
- Salt-free softenersConditioners and electronic descalers, honestly assessed
Questions about Harrow water
Is Harrow a hard water area?
Yes. The median hardness across HA postcode districts is 264 mg/L calcium carbonate, which is very hard. 100% of the 10 districts we hold readings for are hard or very hard (180 mg/L and above).
What is the water hardness in Harrow?
Between 256 and 271 mg/L depending on the district, with a median of 264. The hardest measured district is HA1 at 271 mg/L and the softest is HA8 at 256. Figures come from water company drinking-water tests.
Do I need a water softener in Harrow?
In most HA homes a softener pays for itself: at 264 mg/L kettles, boilers and showers scale up quickly. Check your own district first, because hardness varies from 256 to 271 within the area.
Hardness as mg/L calcium carbonate from water company drinking-water tests and postcode checkers. See the UK hardness map for every area.