Water Hardness and Quality in Maidenhead
Supplied by Thames Water · Windsor & Colnbrook (SWA9)
Maidenhead has very hard water with quality that meets all UK drinking water standards.
Check a specific postcode in Maidenhead
Water Quality Scorecard
Total Hardness
Guideline: 150+ mg/l is considered hard
301mg/l CaCO₃
UK Average: 197.72 mg/l CaCO₃Well Above Average
LowAverageHigh
pH Level
UK Standard: 6.5 – 9.5
7.3pH units
UK Average: 7.43 pH unitsBelow Average
LowAverageHigh
Free Chlorine
Guideline: below 1 mg/l
0.52mg/l
UK Average: 0.45 mg/lAbove Average
LowAverageHigh
Nitrate
UK Standard: max 50 mg/l
16mg/l
UK Average: 16.9 mg/lAverage
LowAverageHigh
Lead
UK Standard: max 10 µg/l
1.2µg/l
UK Average: 1.08 µg/lWell Above Average
LowAverageHigh
Fluoride
UK Standard: max 1.5 mg/l
0.45mg/l
UK Average: 0.19 mg/lWell Above Average
LowAverageHigh
Water Hardness in Maidenhead
Hardness is the most searched water quality metric. It affects limescale buildup in kettles, boilers, and pipes.
301mg/l CaCO₃Very Hard
Soft
Mod. Soft
Slightly Hard
Mod. Hard
Hard
Very Hard
Maidenhead has hard water at 301 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
- Thames Water
- Supply Zone
- Windsor & Colnbrook (SWA9)
- Source Type
- Groundwater
- Treatment Works
- Windsor & Colnbrook Treatment Works
- Last Tested
- 2025-12-31
- Data Source
- Thames Water
Frequently Asked Questions
Is the water hard in Maidenhead?▾
Yes, Maidenhead has hard water at 301 mg/l CaCO₃. This is classified as "Very Hard" on the standard scale. You may notice limescale buildup in kettles and on taps.
Is Maidenhead tap water safe to drink?▾
Yes, tap water in Maidenhead is safe to drink. It is treated and tested by Thames Water and meets all UK Drinking Water Inspectorate standards. All tested parameters are within regulatory limits.
What is the water hardness in Maidenhead?▾
The water hardness in Maidenhead is 301 mg/l CaCO₃, which is classified as "Very Hard". This is above the UK national average of 170 mg/l.
Who supplies water to Maidenhead?▾
Water in Maidenhead is supplied by Thames Water, which serves the London and Thames Valley region. The water comes from underground aquifers and is treated at Windsor & Colnbrook Treatment Works.