Tap water hardness in South Holland
We have published hardness data for 12 cities in South Holland. The median is 7.8 °dH; the hardest water is in Dordrecht (8.1 °dH), the softest in Schiedam (7.6 °dH).
100 % of these cities have hard or very hard water (over 120 mg/L).
Dutch suppliers report °dH; most networks are softened centrally to 5.6–8.4 °dH.
Cities in South Holland, hardest first
| °dH | mg/L | ||
|---|---|---|---|
| Dordrecht | 8.1 | 145 | hard |
| The Hague | 8.1 | 144 | hard |
| Leiden | 8 | 142 | hard |
| Zoetermeer | 8 | 142 | hard |
| Barendrecht | 7.8 | 139 | hard |
| Delft | 7.8 | 139 | hard |
| Hoogvliet | 7.8 | 139 | hard |
| Maassluis | 7.8 | 139 | hard |
| Spijkenisse | 7.8 | 139 | hard |
| Vlaardingen | 7.8 | 139 | hard |
| Capelle aan den IJssel | 7.6 | 136 | hard |
| Schiedam | 7.6 | 136 | hard |