Is Portola, CA Tap Water Safe? Quality & Contaminants

What was found in Portola'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.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate-Nitrite	195000 µg/L 1950% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the city: GOLD MOUNTAIN CSD · 135 people · 2014	1/6	SYR4
Nitrate	528.84 µg/L 5.3% of the EPA limit 10000 µg/L Highest in the city: GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2018	5/6	SYR4
Copper	1 µg/L 0.1% of the EPA limit 1300 µg/L Main supplier: CITY OF PORTOLA · 2,100 people · 2017 Highest in the city: 405.5 µg/L — GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2014	4/6	SYR4
Fluoride	200 µg/L 5% of the EPA limit 4000 µg/L Highest in the city: GRIZZLY RANCH CSD · 102 people · 2017	1/6	SYR4
Arsenic	165.1 µg/L 1651% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: GRIZZLY RANCH CSD · 102 people · 2019	3/6	SYR4
Barium	89.05 µg/L 4.5% of the EPA limit 2000 µg/L Highest in the city: GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2018	4/6	SYR4
Combined Uranium	46.3241 µg/L 154% of the EPA limit, at the 95th percentile of samples — 30 µg/L Highest in the city: GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2019	2/6	SYR4
TTHM	29.1 µg/L 36% of the EPA limit 80 µg/L Main supplier: CITY OF PORTOLA · 2,100 people · 2014	3/6	SYR4
Chloroform	25.25 µg/L No EPA limit set Main supplier: CITY OF PORTOLA · 2,100 people · 2014	3/6	SYR4
Lead	11.875 µg/L 79% of the EPA limit 15 µg/L Highest in the city: GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2014	3/6	SYR4
Chromium	4.8 µg/L 4.8% of the EPA limit 100 µg/L Highest in the city: GRIZZLY RANCH CSD · 102 people · 2017	1/6	SYR4
Bromodichloromethane	3.975 µg/L No EPA limit set Main supplier: CITY OF PORTOLA · 2,100 people · 2014	2/6	SYR4
Bromoform	2 µg/L No EPA limit set Highest in the city: GRIZZLY RANCH CSD · 102 people · 2018	2/6	SYR4
Dibromochloromethane	0.5200 µg/L No EPA limit set Main supplier: CITY OF PORTOLA · 2,100 people · 2014 Highest in the city: 2 µg/L — GRIZZLY RANCH CSD · 102 people · 2018	2/6	SYR4
Total Haloacetic Acids (HAA5)	1.95 µg/L 3.3% of the EPA limit 60 µg/L Highest in the city: GRIZZLY RANCH CSD · 102 people · 2018	1/6	SYR4
Antimony, Total	1 µg/L 17% of the EPA limit 6 µg/L Highest in the city: GRIZZLY LAKE CSD-DELLEKER · 1,314 people · 2018	1/6	SYR4
Dibromoacetic Acid	1 µg/L No EPA limit set Highest in the city: GRIZZLY RANCH CSD · 102 people · 2018	1/6	SYR4
Dichloroacetic Acid	1 µg/L No EPA limit set Highest in the city: GRIZZLY RANCH CSD · 102 people · 2018	1/6	SYR4
Mercury	0.0600 µg/L 3% of the EPA limit 2 µg/L Highest in the city: GRIZZLY RANCH CSD · 102 people · 2017	1/6	SYR4
Lead	0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: CITY OF PORTOLA · 2,100 people · 2023	6/6	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 Portola

Supplier	Population served
CITY OF PORTOLA	2,100
GRIZZLY LAKE CSD-DELLEKER	1,314
GREENHORN CREEK CSD	280
GRIZZLY LAKE CSD-CROCKER/WELCH	215
GOLD MOUNTAIN CSD	135
GRIZZLY RANCH CSD	102

Frequently asked questions about Portola tap water

Is Portola tap water safe to drink?

EPA testing detected 20 contaminants in the water serving Portola. 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 Portola?

6 public water suppliers report drinking-water monitoring for Portola, California to the EPA. Each is listed above with its population served.

What contaminants are in Portola's water?

The contaminants EPA monitoring detected in Portola include Nitrate-Nitrite, Nitrate, Copper, Fluoride, Arsenic. 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.