← San Dimas, CA

Tap water quality report

ZIP 91010 — San Dimas, CA

EPA monitoring across the 2 water suppliers serving ZIP 91010 in San Dimas, CA detected 24 contaminants. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier below, with the EPA limit for each.

2
water suppliers
51,845
people served
24
contaminants found

What was found in ZIP 91010

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

ContaminantLevel vs EPA limitSuppliersSource
Nitrate-Nitrite
4610 µg/L 46%
of the EPA limit 10000 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 747500 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Nitrate
4885.7 µg/L 49%
of the EPA limit 10000 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
2/2 SYR4
Fluoride
853 µg/L 21%
of the EPA limit 4000 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
2/2 SYR4
Copper
234 µg/L 18%
of the EPA limit 1300 µg/L
Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
1/2 SYR4
Barium
200 µg/L 10%
of the EPA limit 2000 µg/L
Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
1/2 SYR4
TTHM
7.38 µg/L 9.2%
of the EPA limit 80 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 19.05 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Trichloroethylene
14 µg/L 280%
of the EPA limit, at the 95th percentile of samples — 5 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
1/2 SYR4
Bromoform
2.8 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 7.76 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Dibromochloromethane
2.75 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 6.935 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Tetrachloroethylene
6.04 µg/L 121%
of the EPA limit, at the 95th percentile of samples — 5 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
1/2 SYR4
Combined Uranium
4.3061 µg/L 14%
of the EPA limit 30 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2018
Highest in the ZIP: 4.7978 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Dichloromethane
3.32 µg/L 66%
of the EPA limit 5 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
1/2 SYR4
Total Haloacetic Acids (HAA5)
3.05 µg/L 5.1%
of the EPA limit 60 µg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 3.24 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Bromodichloromethane
2.17 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 3.22 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Arsenic
3.1 µg/L 31%
of the EPA limit 10 µg/L
Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
1/2 SYR4
Dibromoacetic Acid
1.255 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 3.075 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Monochloroacetic Acid
2.59 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
1/2 SYR4
Chloroform
1.66 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2019
Highest in the ZIP: 1.95 µg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
2/2 SYR4
Dichloroacetic Acid
1.2 µg/L
No EPA limit set
Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
1/2 SYR4
Trichloroacetic Acid
1.2 µg/L
No EPA limit set
Highest in the ZIP: CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2019
1/2 SYR4
PFOS
0.0220 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2024
2/2 UCMR-5
PFHXS
0.0070 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2024
1/2 UCMR-5
PFOA
0.0055 µg/L
No EPA limit set
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2024
1/2 UCMR-5
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: GSWC-SOUTH ARCADIA · 27,072 people · 2023
Highest in the ZIP: 0.0010 mg/L — CAL-AM WATER COMPANY - DUARTE · 24,773 people · 2024
2/2 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.

Water suppliers serving ZIP 91010

SupplierStatePopulation served
GSWC-SOUTH ARCADIA CA 27,072
CAL-AM WATER COMPANY - DUARTE CA 24,773

Frequently asked questions about ZIP 91010 tap water

Is the tap water in ZIP 91010 safe to drink?

EPA testing detected 24 contaminants across the water suppliers serving ZIP 91010. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.

Which water suppliers serve ZIP 91010?

2 public water suppliers report EPA drinking-water monitoring for ZIP 91010. Each is listed above with its population served.

What contaminants are in ZIP 91010's water?

EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Copper, Barium, and others across this ZIP's suppliers. The full list with levels and sources is above.