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Tap water quality report

Westlake Village, CA

EPA monitoring detected 13 contaminants across the 1 water supplier serving Westlake Village. 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
13,898
people served
13
contaminants found
California rankings Lead in California PFAS in California

What was found in Westlake Village'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
TTHM
35 µg/L 44%
of the EPA limit 80 µg/L
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Bromoform
15.649999999999991 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Monochloroacetic Acid
15.535 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Dibromochloromethane
12.649999999999991 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
11 µg/L 18%
of the EPA limit 60 µg/L
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Lithium
9.8 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2025
1/1 UCMR-5
Bromodichloromethane
6.364999999999999 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Dibromoacetic Acid
6.164999999999999 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Chloroform
5.56 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Dichloroacetic Acid
4.229999999999999 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Trichloroacetic Acid
2.2399999999999998 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Monobromoacetic Acid
2.2 µg/L
No EPA limit set
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019
1/1 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2025
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 Westlake Village

SupplierPopulation served
TRIUNFO WATER & SANITATION DISTRICT 13,898

Frequently asked questions about Westlake Village tap water

Is Westlake Village tap water safe to drink?

EPA testing detected 13 contaminants in the water serving Westlake Village. 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 Westlake Village?

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

What contaminants are in Westlake Village's water?

The contaminants EPA monitoring detected in Westlake Village include TTHM, Bromoform, Monochloroacetic Acid, Dibromochloromethane, 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.