Drinking water quality · 2024
· Verified
What's in Diablo Water District, CA tap water
15 contaminants were measured in the Diablo Water District, CA water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 15
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- CA
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound detected in Diablo Water District, CA
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
PFBA
● Detected (no federal limit)Where your water comes from · EPA SDWIS
Diablo Water District, CA buys its drinking water from ESCONDIDO, CITY OF, SAN DIEGO COUNTY WATER AUTHORITY.
Source
Treatment
Distribution
Also buys water from ESCONDIDO, CITY OF, SAN DIEGO COUNTY WATER AUTHORITY.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based2 violations on record · most recent Aug 2014resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 62 ug/LRunning annual avgHighest Quarterly | None set | Within the limit |
| Chlorite | 0.2 mg/LRunning annual avgHighest Quarterly | None set | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 10 ug/LRunning annual avgHighest Quarterly | None set | Within the limit |
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | Not detected ug/LRunning annual avgHighest Quarterly | 0.1 ug/LMCLG | Within the limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChloramineA longer-lasting disinfectant made by combining chlorine with ammonia. | 2.6 mg/LRunning annual avgHighest Quarterly | 4 mg/LMCLG | Within the limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.44 NTURangeSystem-wide | 1 NTUMCL | Within the limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.8 mg/LAverageSystem-wide | 1 mg/LMCLG | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 1.2 mg/LAverageSystem-wide | 10 mg/LMCLG | Within the limit |
| Asbestos | Not detected MFLAverageSystem-wide | 7 MFLMCLG | Within the limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 0.15 mg/L90th percentileAt the tap | 0.3 mg/LMCLG | 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 | 0.2 ug/LMCLG | None detected |
| AluminumA common element sometimes used as a treatment coagulant. | 0.06 mg/LAverageSystem-wide | None set | Detected — no federal limit |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 0.11 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| LithiumA naturally occurring element found in some groundwater. | 11.5 ug/LAverageSystem-wide | None set | Detected — no federal limit |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 0.5 %AverageSystem-wide | None set | Detected — no federal limit |
People also ask about Diablo Water District, CA's water
+Is Diablo Water District, CA tap water safe to drink in 2024?
Every one of the 15 contaminants measured in Diablo Water District, 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 Diablo Water District, CA tap water?
15 contaminants were measured in Diablo Water District, CA's 2024 Consumer Confidence Report, spanning metals, disinfection byproducts, and inorganic chemicals. 8 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 Diablo Water District, 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 Diablo Water District, 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.