Drinking water quality · 2024
· Verified
What's in Costa Mesa, CA tap water
38 contaminants were measured in the Costa Mesa, CA water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 38
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- CA
Where your water comes from · EPA SDWIS
Costa Mesa, CA's drinking water comes from ground water, drawn from 2 sources.
Source
- WELL
- WELL 02
Treatment
Distribution
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-based21 violations on record · most recent Apr 2015resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 2.11 mg/LAverageAverage Amount | 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. | 19 ug/LAverageAverage Amount | None set | Within the limit |
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | 2 ug/LAverageWeymouth | None set | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 3 ug/LAverageAverage Amount | None set | Within the limit |
| NDMA | Not detected ng/LAverageAverage Amount | 3 ng/LPublic health goal | None detected |
| ChlorateA byproduct that can form during disinfection, especially when hypochlorite solutions degrade. | 80 ug/LAverageWeymouth | None set | Detected — no federal limit |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.7 mg/LAverageDiemer | 4 mg/LMCL | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 0.42 mg/LAverageAverage Amount | 10 mg/LMCL | Within the limit |
| ChlorideA naturally occurring salt compound. | 106 mg/LAverageWeymouth | None set | Detected — no federal limit |
| SulfateA naturally occurring mineral from rock and soil. | 225 mg/LAverageWeymouth | None set | Detected — no federal limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 0.0026 mg/L90th percentileAt the tap | 0.015 mg/LAction level | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 0.087 mg/L90th percentileAt the tap | 1.3 mg/LAction level | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 0.124 mg/LAverageDiemer | 2 mg/LMCL | Within the limit |
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | Not detected ug/LAverageAverage Amount | None set | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | 93 ug/LAverageWeymouth | None set | Detected — no federal limit |
| BoronA naturally occurring element from rock and soil. | 0.2 mg/LAverageAverage Amount | None set | Detected — no federal limit |
| CalciumA naturally occurring mineral that contributes to water hardness. | 68 mg/LAverageDiemer | None set | Detected — no federal limit |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | 0.34 ug/LAverageAverage Amount | None set | Detected — no federal limit |
| LithiumA naturally occurring element found in some groundwater. | 22 ug/LAverageAverage Amount | None set | Detected — no federal limit |
| MagnesiumA naturally occurring mineral that contributes to water hardness. | 26 mg/LAverageDiemer | None set | Detected — no federal limit |
| PotassiumA naturally occurring mineral from rock and soil. | 5 mg/LAverageWeymouth | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 105 mg/LAverageWeymouth | None set | Detected — no federal limit |
| Vanadium | 4.5 ug/LAverageAverage Amount | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.12 NTUAverageAverage Amount | 1 NTUMCL | Within the limit |
| AlkalinityA measure of the water's capacity to neutralize acids. | 143 mg/LAverageAverage Amount | None set | Detected — no federal limit |
| Bicarbonate | 163 mg/LAverageAverage Amount | None set | Detected — no federal limit |
| ColorA measure of visible tint in the water. | 2AverageDiemer | None set | Detected — no federal limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 272 mg/LAverageWeymouth | None set | Detected — no federal limit |
| OdorA measure of detectable smell in the water. | 1AverageDiemer | None set | Detected — no federal limit |
| pHA measure of how acidic or basic the water is. | 8.2AverageAverage Amount | None set | Detected — no federal limit |
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 996AverageWeymouth | None set | Detected — no federal limit |
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 2.4 mg/LAverageDiemer | None set | Detected — no federal limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 632 mg/LAverageWeymouth | None set | Detected — no federal limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Nitrate Nitrite | 0.42 mg/LAverageAverage Amount | 10 mg/LMCL | Within the limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | Not detected pCi/LAverageAverage Amount | 5 pCi/LMCL | Within the limit |
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | Not detected pCi/LAverageAverage Amount | 15 pCi/LMCL | Within the limit |
| Gross Beta Particle ActivityGross beta particle activity — a combined measure of beta-emitting radioactive substances. | 4 pCi/LAverageDiemer | None set | Detected — no federal limit |
| UraniumA naturally occurring radioactive metal from erosion of natural deposits. | 1 pCi/LAverageDiemer | 20 pCi/LMCL | Detected — no federal limit |
People also ask about Costa Mesa, CA's water
+Is Costa Mesa, CA tap water safe to drink in 2024?
Every one of the 38 contaminants measured in Costa Mesa, 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 Costa Mesa, CA tap water?
38 contaminants were measured in Costa Mesa, CA's 2024 Consumer Confidence Report, spanning metals, physical & aggregate, and disinfection byproducts. 12 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 Costa Mesa, 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 Costa Mesa, 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.