Drinking water quality · 2024
What's in Modesto, CA tap water
26 contaminants were measured in the Modesto, CA water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 26
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- CA
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | 4.3 ug/LAverageSystem-wide | None set | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 0.11 mg/LAverageSystem-wide | 2 mg/LMCL | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 0.056 mg/L90th percentileAt the tap | 1.3 mg/LAction level | Within the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected ug/L90th percentileAt the tap | None set | None detected |
| LithiumA naturally occurring element found in some groundwater. | 2.11 ug/LAverageSystem-wide | None set | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 4.1 mg/LAverageSystem-wide | 10 mg/LMCL | Within the limit |
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.01 mg/LAverageSystem-wide | 4 mg/LMCL | Within the limit |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 32.4 ug/LRunning annual avgSystem-wide | None set | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 17.8 ug/LRunning annual avgSystem-wide | None set | Within the limit |
| PerchlorateA chemical used in rocket fuel and fireworks that can also form during disinfection. | 0.2 ug/LAverageSystem-wide | None set | Detected — no federal limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. | 1.52 ng/LAverageSystem-wide | 4 ng/LMCL | Within the limit |
| PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. | 0.55 ng/LAverageSystem-wide | 4 ng/LMCL | Within the limit |
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 0.74 ng/LAverageSystem-wide | 10 ng/LMCL | Within the limit |
| Perfluorobutanesulfonic acidPerfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.' | 0.16 ng/LAverageSystem-wide | 500 ng/LNL | Detected — no federal limit |
| Perfluoroheptanoic acidPerfluoroheptanoic acid, a PFAS 'forever chemical.' | 0.044 ng/LAverageSystem-wide | None set | Detected — no federal limit |
| Perfluorohexanoic acidPerfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' | 0.38 ng/LAverageSystem-wide | None set | Detected — no federal limit |
| Perfluoropentanoic acidPerfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' | 0.42 ng/LAverageSystem-wide | None set | Detected — no federal limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 0.85 mg/LAverageSystem-wide | 4 mg/LMCL | Within the limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | 2.11 pCi/LAverageSystem-wide | 15 pCi/LMCL | Within the limit |
| UraniumA naturally occurring radioactive metal from erosion of natural deposits. | 8.19 pCi/LAverageSystem-wide | 20 pCi/LMCL | Detected — no federal limit |
VOCs & pesticides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TrichloroethyleneAn industrial solvent (TCE) used in metal degreasing. | 0.09 ug/LAverageSystem-wide | 5 ug/LMCL | Within the limit |
| DBCP1,2-dibromo-3-chloropropane — a banned soil fumigant pesticide. | 3.4 ng/LAverageSystem-wide | None set | Within the limit |
| TetrachloroethyleneAn industrial solvent (PCE) used in dry cleaning and degreasing. | 0.06 ug/LAverageSystem-wide | 5 ug/LMCL | Within the limit |
| 1,2,3-TCP | 0.32 ng/LAverageSystem-wide | None set | Detected — no federal limit |
| Dichlorodifluoromethane | 0.000003 mg/LAverageSystem-wide | 1 mg/LNL | Detected — no federal limit |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 1.6 %MaximumMonth | 0 %Public health goal | Detected — no federal limit |
People also ask about Modesto, CA's water
+Is Modesto, CA tap water safe to drink in 2024?
Every one of the 26 contaminants measured in Modesto, CA's 2024 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in Modesto, CA tap water?
26 contaminants were measured in Modesto, CA's 2024 Consumer Confidence Report, spanning pfas ("forever chemicals"), metals, and vocs & pesticides. 15 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Where does the data on this page come from?
Every value is transcribed from Modesto, CA's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Modesto, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.