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Tap water quality report

Palo Alto, CA

EPA monitoring detected 16 contaminants across the 1 water supplier serving Palo Alto. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
67,231
people served
16
contaminants found
California rankings Lead in California PFAS in California

What was found in Palo Alto's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
3300 µg/L 33%
of the EPA limit 10000 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Nitrate-Nitrite
3000 µg/L 30%
of the EPA limit 10000 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2018
1/1 SYR4
Barium
614 µg/L 31%
of the EPA limit 2000 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2018
1/1 SYR4
Fluoride
232.5 µg/L 5.8%
of the EPA limit 4000 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2018
1/1 SYR4
TTHM
52.04999999999998 µg/L 65%
of the EPA limit 80 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
51.64999999999998 µg/L 86%
of the EPA limit 60 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Chloroform
50 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Dichloroacetic Acid
29 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Trichloroacetic Acid
23 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Combined Uranium
5.4235999999999995 µg/L 18%
of the EPA limit 30 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2016
1/1 SYR4
Monochloroacetic Acid
5.3500000000000005 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Bromodichloromethane
4.354999999999999 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Monobromoacetic Acid
4.059999999999999 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Arsenic
2.1 µg/L 21%
of the EPA limit 10 µg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2018
1/1 SYR4
Dibromochloromethane
1.7 µg/L
No EPA limit set
Main supplier: CITY OF PALO ALTO · 67,231 people · 2019
1/1 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: CITY OF PALO ALTO · 67,231 people · 2023
1/1 LCR
Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Palo Alto

SupplierPopulation served
CITY OF PALO ALTO 67,231

Frequently asked questions about Palo Alto tap water

Is Palo Alto tap water safe to drink?

EPA testing detected 16 contaminants in the water serving Palo Alto. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Palo Alto?

1 public water supplier report drinking-water monitoring for Palo Alto, California to the EPA. Each is listed above with its population served.

What contaminants are in Palo Alto's water?

The contaminants EPA monitoring detected in Palo Alto include Nitrate, Nitrate-Nitrite, Barium, Fluoride, TTHM. The full list, with the level at the main supplier and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.