Water hardness in Rotterdam
7.6 °dH hard
Tap water in Rotterdam is hard: 7.6 °dH (136 mg/L · 7.9 gpg · 13.6 °fH).
Source: Evides, Mijn waterhardheid (postcode check) (2026) · data checked 2026-10-22
Range across supply zones: 136–139 mg/L.
14 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Centrum (PC 3011, productielocatie Kralingen) | 7.6 | 136 | hard |
| Charlois (PC 3083, productielocatie Berenplaat) | 7.8 | 139 | hard |
| Delfshaven (PC 3024, productielocatie Kralingen) | 7.6 | 136 | hard |
| Feijenoord (PC 3072, productielocatie Kralingen) | 7.6 | 136 | hard |
| Hillegersberg-Schiebroek (PC 3053, productielocatie Kralingen) | 7.6 | 136 | hard |
| Hoek van Holland (PC 3151, productielocatie Berenplaat) | 7.8 | 139 | hard |
| Hoogvliet (PC 3192, productielocatie Berenplaat) | 7.8 | 139 | hard |
| IJsselmonde (PC 3078, productielocatie Kralingen) | 7.6 | 136 | hard |
| Kralingen-Crooswijk (PC 3061, productielocatie Kralingen) | 7.6 | 136 | hard |
| Noord (PC 3035, productielocatie Kralingen) | 7.6 | 136 | hard |
| Overschie (PC 3043, productielocatie Kralingen) | 7.6 | 136 | hard |
| Pernis (PC 3195, productielocatie Berenplaat) | 7.8 | 139 | hard |
| Prins Alexander (PC 3068, productielocatie Kralingen) | 7.6 | 136 | hard |
| Rozenburg (PC 3181, productielocatie Berenplaat) | 7.8 | 139 | hard |
Evides supplies Rotterdam with drinking water made largely from river water of the Maas basin, taken in at the Biesbosch and stored in reservoirs before treatment. The reported hardness is 135.7 mg/L CaCO₃ across 14 supply zones, with values from 135.7 to 139.2 mg/L depending on the street. Kettles, shower heads and washing machine heating elements scale up noticeably, so regular descaling is worthwhile.
Dutch suppliers report °dH; most networks are softened centrally to 5.6–8.4 °dH.
Water data
| Total hardness | 7.6 °dH |
|---|---|
| Utility | Evides |
How Rotterdam compares
- Tap water in Rotterdam is close to the median of the 654 cities we track in the Netherlands (7.5 °dH).
- By hardness it ranks 304 of 654 in the Netherlands (1 = hardest); 53 % of these cities have softer water.
- In Zuid-Holland it is number 5 of 5 cities; the regional median is 8 °dH.
- Nearest city with clearly softer water: Herwijnen, 46 km away (5.8 °dH).
- Nearest city with clearly harder water: Werkendam, 31 km away (10.6 °dH).
Ranking of the hardest and softest water in the Netherlands →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Rotterdam
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H2 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Rotterdam water hard or soft?
It is hard: 136 mg/L as CaCO₃ (7.9 gpg, 7.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rotterdam safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Dutch suppliers report °dH; most networks are softened centrally to 5.6–8.4 °dH.
How many grains per gallon is Rotterdam water?
7.9 gpg, equal to 7.6 °dH, 13.6 °fH or 136 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rotterdam?
For 136 mg/L (7.6 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Rotterdam?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Evides, Mijn waterhardheid (postcode check) (2026). Method: figure published by the water supplier. Evides, Mijn waterhardheid (postcode check) · Outdated figure? Tell us