← Back to summary See all parameters SAINT OUEN DES TOITS · La Gravelle
CA LAVAL AGGLOMÉRATION
Water safety Water safety Parameter Unfiltered tap water Allowed range Filtered Free Chlorinemg CL2/l 0.65 0.2 – 1 0.013 ▲ Total Chlorinemg CL2/l 0.71 No limit 0.14
General General Parameter Unfiltered tap water Allowed range Filtered TemperatureC 22.6 No limit 22.6 Hardnessmg CaCO3/l 138Sampled Jul 2026 80 – 459 138 Hardness fF 13.8Sampled Jul 2026 No limit 13.8 pH 7.8 6.5 – 9.5 7.8 TurbidityNTU 0.3Sampled Jul 2026 ≤ 4 0.03 ColorColor Units 5Sampled Jul 2026 ≤ 15 5 ConductivityμS / cm 420Sampled Jul 2026 ≤ 2,500 420 TDSmg/l 268.8Sampled Jul 2026 estimated 0 – 1,199 268.8 Alkalinitymg CaCO3/l 90Sampled Jul 2026 No limit 90 Bicarbonatemg HCO3/l 109Sampled Jul 2026 No limit 109
Pathogens Pathogens Parameter Unfiltered tap water Allowed range Filtered ClostridiumUFC/100ml 0Sampled Jul 2026 ≤ 0 0 eColiUFC/100ml 0Sampled Jul 2026 ≤ 0 0 BacteriasNMP/100ml 0Sampled Jul 2026 ≤ 0 0 EnterococcusUFC/100ml 0Sampled Jul 2026 ≤ 0 0
Chemical parameters Chemical parameters Parameter Unfiltered tap water Allowed range Filtered Cyanide totalμg CN/l 5Sampled Jun 2026 ≤ 50 0.25 Fluoridemg F/l 0.05Sampled Jun 2026 ≤ 1.5 0.015 Mercuryμg Hg/l 0.01Sampled Jun 2026 ≤ 1 0.001 Nitritesmg NO2/l 0.01Sampled Jul 2026 ≤ 0.5 0.004 Nitratesmg NO3/l 13Sampled Jul 2026 ≤ 50 3.9
Minerals Minerals Parameter Unfiltered tap water Allowed range Filtered Magnesiummg/l 7.3Sampled Jul 2026 No limit 7.3 Calciummg/l 41.4Sampled Jul 2026 No limit 41.4 Potassiummg/l 4.6Sampled Jul 2026 No limit 4.6 Chloridemg/l 57.2Sampled Jul 2026 ≤ 250 57.2
Metals Metals Parameter Unfiltered tap water Allowed range Filtered Aluminiumμg/l 6Sampled Jun 2026 ≤ 200 6 Antimonyμg/l 0.1Sampled Jun 2026 ≤ 5 0.1 Arsenicμg/l 0.2Sampled Jun 2026 ≤ 10 0.1 Bariumμg/l 19Sampled Jun 2026 ≤ 1,000 19 Cadmiumμg/l 0.02Sampled Jun 2026 ≤ 5 0.02 Chromiumμg/l 0.5Sampled Jun 2026 ≤ 50 0.5 Ironμg/l 14Sampled Jul 2026 ≤ 200 14 Manganeseμg/l 0.5Sampled Jul 2026 ≤ 50 0.5 Leadμg/l Not reported ≤ 10 — Seleniumμg/l 0.2Sampled Jun 2026 ≤ 10 0.2 Sodiummg/l 24.9Sampled Jul 2026 ≤ 200 24.9
Chlorine by-products Chlorine by-products Parameter Unfiltered tap water Allowed range Filtered Trichloroethyleneμg/l 0.1Sampled Jun 2026 No limit 0.005 Total Trihalomethanesμg/l 27Sampled Jul 2026 ≤ 100 1.35
Haloacetic acids Haloacetic acids Parameter Unfiltered tap water Allowed range Filtered Total haloacetic acidsμg/l 6.6Sampled Jul 2026 ≤ 60 0.33
Pesticides Pesticides Parameter Unfiltered tap water Allowed range Filtered Chlordaneug/L 0Sampled Jun 2026 ≤ 2 0 Heptachlorug/L 0.001Sampled Jun 2026 ≤ 0.4 0.001 Total pesticidesug/L 0Sampled Jun 2026 ≤ 0.5 0
Herbicides Herbicides Parameter Unfiltered tap water Allowed range Filtered D 2 4ug/L 0.02Sampled Jun 2026 ≤ 70 0.02 Atrazineug/L 0.01Sampled Jun 2026 ≤ 3 0.01
Perfluorinated chemicals Perfluorinated chemicals Parameter Unfiltered tap water Allowed range Filtered PFOAug/L 0.001Sampled Jun 2026 No limit 0.001 PFOSug/L 0.002Sampled Jun 2026 No limit 0.002 PFNAug/L 0.001Sampled Jun 2026 No limit 0.001 Total PFASug/L 0.002Sampled Jun 2026 ≤ 0.1 0 PFAS 4ng/l Not reported No limit — PFAS 21ng/l Not reported No limit —
Other Other Parameter Unfiltered tap water Allowed range Filtered Ammoniamg/l 0.01Sampled Jul 2026 No limit 0.003 Sulfatemg/l 15.2Sampled Jul 2026 No limit 15.2 Uraniumug/L 0.07Sampled Jun 2026 No limit 0.07
Data from the French health inspection of drinking water (Ministry of Health, regional health agencies), per distribution unit. Quality ranges are based on WHO guidelines, EU Directive 2020/2184 and the French public health code.
Your Water Quality
Independent information about tap water quality in France.
Brought to you by
tappwater.co
Data from the French health inspection of drinking water (Ministry of Health, regional health agencies), per distribution unit. Quality ranges are based on WHO guidelines, EU Directive 2020/2184 and the French public health code.
