Water hardness in Tønsberg
2.8 °dH soft
Tap water in Tønsberg is soft: 2.8 °dH (50 mg/L · 2.9 gpg · 5 °fH).
Source: Mattilsynet, Vannverksregisteret – drinking-water analyses (Tønsberg Kommune Vannverk), NLOD 2.0 (2025) · data checked 2026-10-21
Tønsberg is supplied by its municipal waterworks, which in Norway normally takes surface water from lakes, with some towns using groundwater. Norwegian bedrock is mostly granite and gneiss, which gives soft water. The reported hardness is 49.9 mg/L CaCO₃. Kettles and heaters stay fairly clear of scale at this level.
Norwegian waterworks report hardness in °dH or mg/L Ca; most supplies are very soft.
Water data
| Total hardness | 2.8 °dH |
|---|---|
| Utility | Tønsberg Kommune |
How Tønsberg compares
- Tap water in Tønsberg is 40 % harder than the median of the 89 cities we track in Norway (2 °dH).
- By hardness it ranks 24 of 89 in Norway (1 = hardest); 74 % of these cities have softer water.
- In Vestfold it is number 1 of 3 cities; the regional median is 1.4 °dH.
- Nearest city with clearly softer water: Færder, 4 km away (1.4 °dH).
- Nearest city with clearly harder water: Ringerike, 100 km away (5 °dH).
Ranking of the hardest and softest water in Norway →
What it means at home
- Little or no limescale in kettles, water heaters or washing machines.
- Soap lathers easily; water does not dry skin or hair.
- Dishwasher: salt setting at minimum or off.
- No softener needed; a jug filter only changes taste.
How much salt will you use for softening?
No. Water this soft does not need softening.
Descale a coffee machine or kettle about every 6 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Tønsberg
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 3 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Tønsberg water hard or soft?
It is soft: 50 mg/L as CaCO₃ (2.9 gpg, 2.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Tønsberg safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Norwegian waterworks report hardness in °dH or mg/L Ca; most supplies are very soft.
How many grains per gallon is Tønsberg water?
2.9 gpg, equal to 2.8 °dH, 5 °fH or 50 mg/L calcium carbonate.
What dishwasher salt setting should I use in Tønsberg?
For 50 mg/L (2.8 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Tønsberg?
No. With soft water a softener adds nothing.
Source
Source: Mattilsynet, Vannverksregisteret – drinking-water analyses (Tønsberg Kommune Vannverk), NLOD 2.0 (2025). Method: computed from supplier's calcium and magnesium. Mattilsynet, Vannverksregisteret – drinking-water analyses (Tønsberg Kommune Vannverk), NLOD 2.0 · Outdated figure? Tell us