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Tap water quality report

Lower Lake, CA

EPA monitoring detected 18 contaminants across the 4 water suppliers serving Lower Lake. 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.

4
water suppliers
1,579
people served
18
contaminants found
California rankings Lead in California PFAS in California

What was found in Lower Lake'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
7100 µg/L 71%
of the EPA limit 10000 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Fluoride
582 µg/L 15%
of the EPA limit 4000 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
4/4 SYR4
Barium
310 µg/L 16%
of the EPA limit 2000 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
TTHM
85.896 µg/L 107%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
4/4 SYR4
Total Haloacetic Acids (HAA5)
39.55 µg/L 66%
of the EPA limit 60 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Dibromochloromethane
34.39 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Bromodichloromethane
27.215 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Chloroform
26.3045 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
4/4 SYR4
Trichloroacetic Acid
17.16 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Arsenic
15.6 µg/L 156%
of the EPA limit, at the 95th percentile of samples — 10 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Dichloroacetic Acid
13.45 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Dibromoacetic Acid
12.6 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
2/4 SYR4
Bromoform
10.825 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Chromium
5.39 µg/L 5.4%
of the EPA limit 100 µg/L
Highest in the city: BAYCLIFF WATER · 70 people · 2018
1/4 SYR4
Diquat
2.8 µg/L 14%
of the EPA limit 20 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Mercury
2 µg/L 100%
of the EPA limit 2 µg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Monobromoacetic Acid
1.3 µg/L
No EPA limit set
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2019
1/4 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: LOWER LAKE COUNTY WATER DISTRICT · 1,326 people · 2025
Highest in the city: 0.0080 mg/L — SUNRISE SHORE MUTUAL WATER COMPANY · 83 people · 2025
4/4 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 Lower Lake

SupplierPopulation served
LOWER LAKE COUNTY WATER DISTRICT 1,326
CDF-KONOCTI CONSERVATION CAMP NO. 27 100
SUNRISE SHORE MUTUAL WATER COMPANY 83
BAYCLIFF WATER 70

Frequently asked questions about Lower Lake tap water

Is Lower Lake tap water safe to drink?

EPA testing detected 18 contaminants in the water serving Lower Lake. 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 Lower Lake?

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

What contaminants are in Lower Lake's water?

The contaminants EPA monitoring detected in Lower Lake include Nitrate, Fluoride, Barium, TTHM, Total Haloacetic Acids (HAA5). 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.