How hard is the water in Novato, CA?

Tap water hardness
63mg/L
3.7gpg
Moderately hard

Reported by Marin Municipal Water District · October 2025

CA typical
121 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

The water in Novato carries roughly 63 mg/L of dissolved calcium and magnesium, or 3.7 grains per gallon. That is moderately hard water. The number comes from Marin Municipal Water District, dated October 2025.

Novato on the hardness scale, with nearby cities
060120180240300360+CA typical 121Fairfax: 56 mg/LFairfax 56San Anselmo: 56 mg/LSan Anselmo 56San Rafael: 56 mg/LSan Rafael 56Larkspur: 56 mg/LLarkspur 56Kentfield: 56 mg/LKentfield 56Corte Madera: 56 mg/LCorte Madera 56Mill Valley: 56 mg/LMill Valley 56Strawberry: 56 mg/LStrawberry 56Lucas Valley-Marinwood: 63 mg/LLucas Valley-Marinwood 63Petaluma: 105 mg/LPetaluma 105Novato 63mg/L as calcium carbonate060120180240300360+CA 121Fairfax: 56 mg/LFairfax 56San Anselmo: 56 mg/LSan Anselmo 56San Rafael: 56 mg/LSan Rafael 56Larkspur: 56 mg/LLarkspur 56Kentfield: 56 mg/LKentfield 56Lucas Valley-Marinwood: 63 mg/LLucas Vall. 6363 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 63 mg/L, Novato is 58 mg/L below the typical California figure of 121. Of the 10 nearest cities we track, 8 have softer water and 1 has harder. The range nearby runs from 56 mg/L in Fairfax to 105 in Petaluma.

What 63 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Novato

3 people × 75 gallons a day × 3.7 gpg = 828 grains a day. A 24,000-grain unit regenerates about every 28 days.

Size it for your household

EPA record for Novato's water system

Marin Municipal Water District · PWSID CA2110002

No health-based violations since 2016

Serves about 188,116 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

TapWaterData ties Novato to this system. EPA's service-area records do not name Novato, so check the utility printed on your water bill.

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Novato water hard?

Somewhat. It measures about 63 mg/L (3.7 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Novato in grains per gallon?

About 3.7 gpg. One grain per gallon equals 17.1 mg/L, so 63 mg/L divided by 17.1 gives 3.7.

What size water softener do I need in Novato?

For 3 people using 75 gallons each per day, 3.7 gpg works out to about 828 grains a day. A 24,000-grain softener covers that with a regeneration about every 28 days.

Has the Novato water system had EPA violations?

EPA records show no health-based violations for Marin Municipal Water District since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, October 6, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.