Water hardness in Novato
5.9 gpg moderately hard
Tap water in Novato is moderately hard: 5.9 gpg (101 mg/L · 5.6 °dH · 10.1 °fH).
Source: NMWD 2025 Annual Water Quality Report (Novato, English) (2025) · data checked 2026-10-20
Range across supply zones: 74–120 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| SCWA supply (purchased Sonoma County Water Agency water) | 6.4 | 110 | moderately hard |
| Stafford Water Treatment Plant (NMWD Stafford Lake supply) | 5.3 | 91 | moderately hard |
North Marin Water District's 2025 report lists two supplies for Novato. Water purchased from the Sonoma County Water Agency averages 110 mg/L (6.4 gpg), range 110 to 120 mg/L. The district's own Stafford Lake treatment plant averages 91 mg/L (5.3 gpg), range 74 to 100 mg/L. The page shows the median of 100.5 mg/L (5.9 gpg) across both. The report does not say how the supplies are split by neighborhood, so your tap may sit nearer either value. Both are moderately hard, and scale builds up slowly.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 5.9 gpg |
|---|---|
| Utility | North Marin Water District (NMWD) |
How Novato compares
- Tap water in Novato is 35 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1014 of 1372 in the United States (1 = hardest); 26 % of these cities have softer water.
- In California it is number 248 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Sonoma, 22 km away (3.2 gpg).
- Nearest city with clearly harder water: Petaluma, 16 km away (9.5 gpg).
Ranking of the hardest and softest water in the United States →
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 Novato
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| 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 Novato water hard or soft?
It is moderately hard: 101 mg/L as CaCO₃ (5.9 gpg, 5.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Novato safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Novato water?
5.9 gpg, equal to 5.6 °dH, 10.1 °fH or 101 mg/L calcium carbonate.
What dishwasher salt setting should I use in Novato?
For 101 mg/L (5.6 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Novato?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: NMWD 2025 Annual Water Quality Report (Novato, English) (2025). Method: figure published by the water supplier. NMWD 2025 Annual Water Quality Report (Novato, English) · Outdated figure? Tell us