Water Hardness and Quality in Harrow on the Hill
Supplied by Affinity Water · Harrow South (AF093)
Harrow on the Hill has very hard water with quality that meets all UK drinking water standards.
Check a specific postcode in Harrow on the Hill
Water Quality Scorecard
Total Hardness
Guideline: 150+ mg/l is considered hard
363mg/l CaCO₃
UK Average: 197.72 mg/l CaCO₃Well Above Average
LowAverageHigh
pH Level
UK Standard: 6.5 – 9.5
7.2pH units
UK Average: 7.43 pH unitsWell Below Average
LowAverageHigh
Free Chlorine
Guideline: below 1 mg/l
0.35mg/l
UK Average: 0.45 mg/lBelow Average
LowAverageHigh
Nitrate
UK Standard: max 50 mg/l
31mg/l
UK Average: 16.9 mg/lWell Above Average
LowAverageHigh
Lead
UK Standard: max 10 µg/l
2.79µg/l
UK Average: 1.08 µg/lWell Above Average
LowAverageHigh
Fluoride
UK Standard: max 1.5 mg/l
0.124mg/l
UK Average: 0.19 mg/lAverage
LowAverageHigh
Water Hardness in Harrow on the Hill
Hardness is the most searched water quality metric. It affects limescale buildup in kettles, boilers, and pipes.
363mg/l CaCO₃Very Hard
Soft
Mod. Soft
Slightly Hard
Mod. Hard
Hard
Very Hard
Harrow on the Hill has hard water at 363 mg/l. You will likely experience significant limescale buildup in kettles, boilers, and on bathroom surfaces. Many residents in your area use water softeners or anti-limescale products.
Water Source Information
- Water Company
- Affinity Water
- Supply Zone
- Harrow South (AF093)
- Source Type
- Groundwater
- Treatment Works
- Harrow South Treatment Works
- Last Tested
- 2025-12-31
- Data Source
- Affinity Water
Frequently Asked Questions
Is the water hard in Harrow on the Hill?▾
Yes, Harrow on the Hill has hard water at 363 mg/l CaCO₃. This is classified as "Very Hard" on the standard scale. You may notice limescale buildup in kettles and on taps.
Is Harrow on the Hill tap water safe to drink?▾
Yes, tap water in Harrow on the Hill is safe to drink. It is treated and tested by Affinity Water and meets all UK Drinking Water Inspectorate standards. All tested parameters are within regulatory limits.
What is the water hardness in Harrow on the Hill?▾
The water hardness in Harrow on the Hill is 363 mg/l CaCO₃, which is classified as "Very Hard". This is above the UK national average of 170 mg/l.
Who supplies water to Harrow on the Hill?▾
Water in Harrow on the Hill is supplied by Affinity Water, which serves the South East England region. The water comes from underground aquifers and is treated at Harrow South Treatment Works.