Water Hardness and Quality in Osterley
Supplied by Thames Water · Hounslow Heath (NLW25)
Osterley has hard water with quality that meets all UK drinking water standards.
Check a specific postcode in Osterley
Water Quality Scorecard
Total Hardness
Guideline: 150+ mg/l is considered hard
263mg/l CaCO₃
UK Average: 197.72 mg/l CaCO₃Above Average
LowAverageHigh
pH Level
UK Standard: 6.5 – 9.5
7.7pH units
UK Average: 7.43 pH unitsWell Above Average
LowAverageHigh
Free Chlorine
Guideline: below 1 mg/l
0.69mg/l
UK Average: 0.45 mg/lWell Above Average
LowAverageHigh
Nitrate
UK Standard: max 50 mg/l
23mg/l
UK Average: 16.9 mg/lAbove Average
LowAverageHigh
Lead
UK Standard: max 10 µg/l
1.5µg/l
UK Average: 1.08 µg/lWell Above Average
LowAverageHigh
Fluoride
UK Standard: max 1.5 mg/l
0.14mg/l
UK Average: 0.19 mg/lAbove Average
LowAverageHigh
Water Hardness in Osterley
Hardness is the most searched water quality metric. It affects limescale buildup in kettles, boilers, and pipes.
263mg/l CaCO₃Hard
Soft
Mod. Soft
Slightly Hard
Mod. Hard
Hard
Very Hard
Osterley has hard water at 263 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
- Hounslow Heath (NLW25)
- Source Type
- River
- Treatment Works
- Hounslow Heath Treatment Works
- Last Tested
- 2025-12-31
- Data Source
- Thames Water
Frequently Asked Questions
Is the water hard in Osterley?▾
Yes, Osterley has hard water at 263 mg/l CaCO₃. This is classified as "Hard" on the standard scale. You may notice limescale buildup in kettles and on taps.
Is Osterley tap water safe to drink?▾
Yes, tap water in Osterley 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 Osterley?▾
The water hardness in Osterley is 263 mg/l CaCO₃, which is classified as "Hard". This is above the UK national average of 170 mg/l.
Who supplies water to Osterley?▾
Water in Osterley is supplied by Thames Water, which serves the London and Thames Valley region. The water comes from river sources and is treated at Hounslow Heath Treatment Works.