Palo Alto, CA water hardness

Tap water hardness
29mg/L
1.7gpg
Soft

Reported by City of Palo Alto · October 2025

CA typical
121 mg/L
EPA health violations since 2016
0
Data
Utility report

Palo Alto water measures 29 mg/L (1.7 gpg) of hardness, soft by USGS standards. The number comes from City of Palo Alto, dated October 2025.

Palo Alto on the hardness scale, with nearby cities
060120180240300360+CA typical 121North Fair Oaks: 32 mg/LNorth Fair Oaks 32Woodside: 32 mg/LWoodside 32Redwood City: 32 mg/LRedwood City 32Menlo Park: 46 mg/LMenlo Park 46Mountain View: 134 mg/LMountain View 134Stanford: 146 mg/LStanford 146Cupertino: 186 mg/LCupertino 186Los Altos Hills: 274 mg/LLos Altos Hills 274Los Altos: 298 mg/LLos Altos 298Sunnyvale: 298 mg/LSunnyvale 298Palo Alto 29mg/L as calcium carbonate060120180240300360+CA 121North Fair Oaks: 32 mg/LNorth Fair. 32Menlo Park: 46 mg/LMenlo Park 46Mountain View: 134 mg/LMountain V. 134Stanford: 146 mg/LStanford 146Los Altos Hills: 274 mg/LLos Altos. 274Los Altos: 298 mg/LLos Altos 29829 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Palo Alto sits 92 mg/L below the typical California figure of 121. None of the 10 nearest cities we track has softer water. The range nearby runs from 32 mg/L in North Fair Oaks to 298 in Los Altos.

What 29 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

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

Nothing, as far as hardness goes. At 29 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Palo Alto's water system

City of Palo Alto · PWSID CA4310009

No health-based violations since 2016

Serves about 67,658 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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 Palo Alto water hard?

No. It measures about 29 mg/L (1.7 grains per gallon), which the USGS classes as soft.

What is the water hardness in Palo Alto in grains per gallon?

About 1.7 gpg. One grain per gallon equals 17.1 mg/L, so 29 mg/L divided by 17.1 gives 1.7.

Has the Palo Alto water system had EPA violations?

EPA records show no health-based violations for City of Palo Alto since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, October 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.