What was found in Calimesa'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 | 9000 µg/L 90% of the EPA limit 10000 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019 | 4/4 | SYR4 |
| Nitrate-Nitrite | 8600 µg/L 86% of the EPA limit 10000 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019 | 1/4 | SYR4 |
| Fluoride | 2075 µg/L 52% of the EPA limit 4000 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019 | 4/4 | SYR4 |
| Copper | 62 µg/L 4.8% of the EPA limit 1300 µg/L Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 1/4 | SYR4 |
| Barium | 43.85 µg/L 2.2% of the EPA limit 2000 µg/L Highest in the city: SHARONDALE MESA HOA · 340 people · 2018 | 3/4 | SYR4 |
| TTHM | 10.75 µg/L 13% of the EPA limit 80 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 40 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 4/4 | SYR4 |
| Chloroform | 24.639999999999997 µg/L No EPA limit set Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 2/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 2.339999999999999 µg/L 3.9% of the EPA limit 60 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 19.65 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 2/4 | SYR4 |
| Dichloroacetic Acid | 13.389999999999999 µg/L No EPA limit set Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 1/4 | SYR4 |
| Chromium | 12.45 µg/L 12% of the EPA limit 100 µg/L Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 3/4 | SYR4 |
| Dibromochloromethane | 3.7 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 11.279999999999998 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 3/4 | SYR4 |
| Bromodichloromethane | 1.6799999999999993 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 8.94 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 3/4 | SYR4 |
| Bromoform | 5.675000000000001 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 8.919999999999996 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 4/4 | SYR4 |
| Arsenic | 5.02 µg/L 50% of the EPA limit 10 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019 | 1/4 | SYR4 |
| Monobromoacetic Acid | 4.82 µg/L No EPA limit set Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 1/4 | SYR4 |
| Trichloroacetic Acid | 4.6 µg/L No EPA limit set Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 1/4 | SYR4 |
| Dibromoacetic Acid | 2.339999999999999 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2019
Highest in the city: 2.715 µg/L — RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 2/4 | SYR4 |
| Monochloroacetic Acid | 2.68 µg/L No EPA limit set Highest in the city: RANCHO CALIMESA MOBILE HOME PARK · 296 people · 2019 | 1/4 | SYR4 |
| Combined Uranium | 1.937 µg/L 6.5% of the EPA limit 30 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2015 | 1/4 | SYR4 |
| Thallium, Total | 1.1 µg/L 55% of the EPA limit 2 µg/L Main supplier: SOUTH MESA WC · 10,108 people · 2019 | 1/4 | SYR4 |
| Pfpea | 0.0089 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2023 | 1/4 | UCMR-5 |
| Pfhxa | 0.0068 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2023 | 1/4 | UCMR-5 |
| PFBS | 0.0047 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2023 | 1/4 | UCMR-5 |
| PFHXS | 0.0035 µg/L No EPA limit set Main supplier: SOUTH MESA WC · 10,108 people · 2023 | 1/4 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: SOUTH MESA WC · 10,108 people · 2025
Highest in the city: 0.00060 mg/L — SHARONDALE MESA HOA · 340 people · 2024 | 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 Calimesa
| Supplier | Population served |
|---|---|
| SOUTH MESA WC | 10,108 |
| PLANTATION ON THE LAKE PARK | 897 |
| SHARONDALE MESA HOA | 340 |
| RANCHO CALIMESA MOBILE HOME PARK | 296 |
Frequently asked questions about Calimesa tap water
Is Calimesa tap water safe to drink?
EPA testing detected 25 contaminants in the water serving Calimesa. 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 Calimesa?
4 public water suppliers report drinking-water monitoring for Calimesa, California to the EPA. Each is listed above with its population served.
What contaminants are in Calimesa's water?
The contaminants EPA monitoring detected in Calimesa include Nitrate, Nitrate-Nitrite, Fluoride, Copper, Barium. 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.