Water hardness in Haarlem
7.9 °dH hard
Tap water in Haarlem is hard: 7.9 °dH (141 mg/L · 8.2 gpg · 14.1 °fH).
Source: PWN, waterhardheid (FAQ) (2026) · data checked 2026-10-29
PWN makes drinking water for North Holland largely from IJsselmeer water, treated at Andijk and partly infiltrated into the dunes, with softening at its Heemskerk plant. The reported hardness is 141.0 mg/L CaCO₃. 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 | 7.9 °dH |
|---|---|
| Utility | PWN |
How Haarlem compares
- Tap water in Haarlem is 5 % harder than the median of the 654 cities we track in the Netherlands (7.5 °dH).
- By hardness it ranks 198 of 654 in the Netherlands (1 = hardest); 67 % of these cities have softer water.
- In North Holland it is number 2 of 13 cities; the regional median is 7.9 °dH.
- Nearest city with clearly softer water: Loenen aan de Vecht, 32 km away (6.2 °dH).
- Nearest city with clearly harder water: Beusichem, 65 km away (12.4 °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 Haarlem
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| 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 Haarlem water hard or soft?
It is hard: 141 mg/L as CaCO₃ (8.2 gpg, 7.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Haarlem 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 Haarlem water?
8.2 gpg, equal to 7.9 °dH, 14.1 °fH or 141 mg/L calcium carbonate.
What dishwasher salt setting should I use in Haarlem?
For 141 mg/L (7.9 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Haarlem?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: PWN, waterhardheid (FAQ) (2026). Method: figure published by the water supplier. PWN, waterhardheid (FAQ) · Outdated figure? Tell us