Water hardness in Lohja
4.1 °dH moderately hard
Tap water in Lohja is moderately hard: 4.1 °dH (73 mg/L · 4.3 gpg · 7.3 °fH).
Source: Lohjan vesilaitos - Veden kovuus (2026) · data checked 2026-10-23
Range across supply zones: 45–136 mg/L.
11 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Karjalohja | 3.5 | 63 | moderately hard |
| Keskikaupunki | 7.6 | 136 | hard |
| Kirkniemi | 6.1 | 109 | moderately hard |
| Lohjan asema | 4.5 | 80 | moderately hard |
| Länsi-Lohja | 4.5 | 80 | moderately hard |
| Muijala | 4.1 | 73 | moderately hard |
| Nummentausta | 5.1 | 91 | moderately hard |
| Nummi | 2.5 | 45 | soft |
| Pusula | 2.5 | 45 | soft |
| Sammatti | 3.7 | 66 | moderately hard |
| Saukkola | 2.5 | 45 | soft |
Finnish waterworks use lake water, often treated or recharged through glacial esker deposits, or natural groundwater. Hardness here is above what the mostly granite bedrock would suggest, so local deposits or the supplier's source are likely to play a role. The figure shown, 73.2 mg/L CaCO₃, is the median across 11 supply zones, which range from 44.6 to 135.7 mg/L, so it depends on which zone your street is in. Kettles and shower screens collect some limescale over time, and regular descaling is usually enough.
Finnish waterworks report hardness in °dH; most supplies are soft.
Water data
| Total hardness | 4.1 °dH |
|---|---|
| Utility | Lohjan vesilaitos (City of Lohja water and sewage utility) |
How Lohja compares
- Tap water in Lohja is 18 % harder than the median of the 76 cities we track in Finland (3.5 °dH).
- By hardness it ranks 25 of 76 in Finland (1 = hardest); 67 % of these cities have softer water.
- In 01 it is number 4 of 6 cities; the regional median is 4.2 °dH.
- Nearest city with clearly softer water: Helsinki, 49 km away (3 °dH).
- Nearest city with clearly harder water: Nurmijärvi, 47 km away (5.1 °dH).
Ranking of the hardest and softest water in Finland →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Lohja
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| Hoover | S1 |
| LG | H1 |
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 Lohja water hard or soft?
It is moderately hard: 73 mg/L as CaCO₃ (4.3 gpg, 4.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Lohja safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Finnish waterworks report hardness in °dH; most supplies are soft.
How many grains per gallon is Lohja water?
4.3 gpg, equal to 4.1 °dH, 7.3 °fH or 73 mg/L calcium carbonate.
What dishwasher salt setting should I use in Lohja?
For 73 mg/L (4.1 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Lohja?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Lohjan vesilaitos - Veden kovuus (2026). Method: figure published by the water supplier. Lohjan vesilaitos - Veden kovuus · Outdated figure? Tell us