What was found in Modesto's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 768000 µg/L 7680% of the EPA limit, in the worst sample — 10000 µg/L | 13/17 | SYR4 |
| Nitrate | 22700 µg/L 227% of the EPA limit, in the worst sample — 10000 µg/L | 15/17 | SYR4 |
| Fluoride | 1200 µg/L 30% of the EPA limit 4000 µg/L | 10/17 | SYR4 |
| Barium | 510 µg/L 26% of the EPA limit 2000 µg/L | 9/17 | SYR4 |
| TTHM | 98.16 µg/L 123% of the EPA limit, in the worst sample — 80 µg/L | 11/17 | SYR4 |
| Chloroform | 94.45 µg/L No EPA limit set | 4/17 | SYR4 |
| Combined Uranium | 71.52 µg/L 238% of the EPA limit, in the worst sample — 30 µg/L | 12/17 | SYR4 |
| Total Haloacetic Acids (HAA5) | 61.1 µg/L 102% of the EPA limit, in the worst sample — 60 µg/L | 6/17 | SYR4 |
| Trichloroethylene | 54 µg/L 1080% of the EPA limit, in the worst sample — 5 µg/L | 1/17 | SYR4 |
| Dichloroacetic Acid | 32.9 µg/L No EPA limit set | 3/17 | SYR4 |
| Trichloroacetic Acid | 32.2 µg/L No EPA limit set | 3/17 | SYR4 |
| Arsenic | 28 µg/L 280% of the EPA limit, in the worst sample — 10 µg/L | 12/17 | SYR4 |
| Tetrachloroethylene | 22 µg/L 440% of the EPA limit, in the worst sample — 5 µg/L | 1/17 | SYR4 |
| Chromium | 21 µg/L 21% of the EPA limit 100 µg/L | 5/17 | SYR4 |
| Lithium | 21 µg/L No EPA limit set | 2/17 | UCMR-5 |
| Selenium | 14 µg/L 28% of the EPA limit 50 µg/L | 4/17 | SYR4 |
| Bromodichloromethane | 13.8 µg/L No EPA limit set | 4/17 | SYR4 |
| Dibromochloromethane | 9.92 µg/L No EPA limit set | 5/17 | SYR4 |
| Bromoform | 6.67 µg/L No EPA limit set | 9/17 | SYR4 |
| Monochloroacetic Acid | 5.3 µg/L No EPA limit set | 3/17 | SYR4 |
| Dibromoacetic Acid | 4.6 µg/L No EPA limit set | 6/17 | SYR4 |
| Gross Beta Particle Activity | 3.67 pCi/L No EPA limit set | 2/17 | SYR4 |
| Beryllium, Total | 2 µg/L 50% of the EPA limit 4 µg/L | 1/17 | SYR4 |
| Monobromoacetic Acid | 2 µg/L No EPA limit set | 3/17 | SYR4 |
| Bromate | 1.7 µg/L 17% of the EPA limit 10 µg/L | 1/17 | SYR4 |
| Combined Radium (-226 And -228) | 1.19 pCi/L 24% of the EPA limit 5 pCi/L | 1/17 | SYR4 |
| Cadmium | 1 µg/L 20% of the EPA limit 5 µg/L | 1/17 | SYR4 |
| 1,1-Dichloroethylene | 0.9900 µg/L 14% of the EPA limit 7 µg/L | 1/17 | SYR4 |
| Nitrite | 0.9500 µg/L 0.1% of the EPA limit 1000 µg/L | 5/17 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.7000 µg/L 350% of the EPA limit, in the worst sample — 0.2000 µg/L | 6/17 | SYR4 |
| Ethylbenzene | 0.5200 µg/L 0.1% of the EPA limit 700 µg/L | 1/17 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 0.2000 µg/L 3.3% of the EPA limit 6 µg/L | 1/17 | SYR4 |
| PFOS | 0.0260 µg/L No EPA limit set | 1/17 | UCMR-5 |
| Lead | 0.0120 mg/L 80% of the EPA limit 0.0150 mg/L | 16/17 | LCR |
| PFHXS | 0.0093 µg/L No EPA limit set | 1/17 | UCMR-5 |
| PFOA | 0.0086 µg/L No EPA limit set | 1/17 | UCMR-5 |
| Pfpea | 0.0067 µg/L No EPA limit set | 1/17 | UCMR-5 |
| Pfhxa | 0.0061 µg/L No EPA limit set | 1/17 | UCMR-5 |
| PFBS | 0.0043 µg/L No EPA limit set | 1/17 | UCMR-5 |
| Pfhpa | 0.0036 µg/L No EPA limit set | 1/17 | UCMR-5 |
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 single worst sample on
record — 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 Modesto
| Supplier | Population served |
|---|---|
| MODESTO, CITY OF | 218,771 |
| CITY OF MODESTO - SALIDA | 14,537 |
| CITY OF WATERFORD | 8,788 |
| CITY OF MODESTO - DEL RIO | 1,327 |
| CITY OF MODESTO - SOUTH TURLOCK | 1,099 |
| CITY OF MODESTO - GRAYSON | 914 |
| HILLSVIEW HOMES | 887 |
| RIVERDALE PARK TRACT CSD | 610 |
| WATERFORD - HICKMAN | 597 |
| PARK HEIGHTS MUTUAL WATER CO | 250 |
| CITY OF MODESTO - WALNUT MANOR | 175 |
| CITY OF MODESTO - NORTH TURLOCK | 172 |
| CITY OF MODESTO - CENTRAL TURLOCK | 119 |
| MORNINGSIDE MOBILEHOME PARK | 67 |
| COUNTRY WESTERN MHRV | 55 |
| RIVER ROAD MUTUAL WATER COMPANY | 26 |
| MODESTO IRRIGATION DISTRICT | 23 |
Frequently asked questions about Modesto tap water
Is Modesto tap water safe to drink?
EPA testing detected 40 contaminants in the water serving Modesto. 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 Modesto?
17 public water suppliers report drinking-water monitoring for Modesto, California to the EPA. Each is listed above with its population served.
What contaminants are in Modesto's water?
The contaminants EPA monitoring detected in Modesto include Nitrate-Nitrite, Nitrate, Fluoride, Barium, TTHM. The full list, with the highest level found 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.