# El Monte, CA — Drinking Water Quality (2024)

> Contaminant levels for the El Monte, CA public water system from its 2024 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/el-monte/2024
- JSON API: https://www.thewatermap.com/api/water/ca/el-monte/2024
- Source: the utility's annual Consumer Confidence Report (CCR)
- Verification: transcribed by a model, cross-checked by a second model, approved before publishing
- Reporting year: 2024
- Contaminants measured: 25
- Contaminants with a federal limit: 16
- Contaminants at or above the federal limit: 3
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 0.36–1.28 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| HAA5 | Disinfection byproducts | 0–0.93 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| TTHM | Disinfection byproducts | 0–6.1 ug/L (Range) | System-wide | 80 ug/L (MCL) | Within the limit |
| Chloride | Inorganic chemicals | 12–24 mg/L (Range) | System-wide | 500 mg/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.32–0.86 mg/L (Range) | System-wide | 2 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 2.4–7.1 mg/L (Range) | System-wide | 10 mg/L (MCL) | Within the limit |
| Sulfate | Inorganic chemicals | 21–66 mg/L (Range) | System-wide | 500 mg/L (MCL) | Within the limit |
| Chromium, Hexavalent | Metals | 3.5–5.6 ug/L (Range) | System-wide | 10 ug/L (MCL) | Within the limit |
| Copper | Metals | 0.65 mg/L (90th percentile) | At the tap | 1.3 mg/L (Action level) | Within the limit |
| Iron | Metals | Not detected ug/L (Reported level) | System-wide | 300 ug/L (MCL) | None detected |
| Lead | Metals | 0.004 ug/L (90th percentile) | At the tap | 15 ug/L (Action level) | Within the limit |
| Sodium | Metals | 14–25 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Escherichia coli (E. coli) | Microbial | 0 (Reported level) | System-wide | No federal limit | None detected |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | 0–4.6 ng/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorohexanoic acid | PFAS ("forever chemicals") | Not detected ng/L (Reported level) | System-wide | No federal limit | None detected |
| Perfluoropentanoic acid | PFAS ("forever chemicals") | Not detected ng/L (Reported level) | System-wide | No federal limit | None detected |
| PFOS | PFAS ("forever chemicals") | Not detected ng/L (Reported level) | System-wide | No federal limit | None detected |
| Hardness | Physical & aggregate | 200–380 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Specific Conductance | Physical & aggregate | 460–800 (Range) | System-wide | 1 (MCL) | At or above the limit |
| Total Dissolved Solids | Physical & aggregate | 270–500 mg/L (Range) | System-wide | 1 mg/L (MCL) | At or above the limit |
| Turbidity | Physical & aggregate | 0–1.8 mg/L (Range) | System-wide | 5 mg/L (MCL) | Within the limit |
| Gross Alpha | Radionuclides | 0–7.8 pCi/L (Range) | System-wide | 15 pCi/L (MCL) | Within the limit |
| Uranium | Radionuclides | 2.2–8 pCi/L (Range) | System-wide | 20 pCi/L (MCL) | Within the limit |
| Tetrachloroethylene | VOCs & pesticides | 0–1.6 ug/L (Range) | System-wide | 5 ug/L (MCL) | Within the limit |
| Trichloroethylene | VOCs & pesticides | 0–5.5 ug/L (Range) | System-wide | 5 ug/L (MCL) | At or above the limit |

## What these contaminants are

- **Chlorine** — A disinfectant added to drinking water to kill bacteria and viruses. Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.
- **HAA5** — Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. Long-term exposure above the federal limit is associated with an increased cancer risk.
- **TTHM** — Total trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. Long-term exposure above the federal limit is linked to liver, kidney, and central-nervous-system effects and increased cancer risk.
- **Chloride** — A naturally occurring salt compound. Regulated only as a secondary (cosmetic) standard; high levels cause a salty taste and can corrode pipes.
- **Fluoride** — A mineral often added to drinking water to help prevent tooth decay. Beneficial at low levels, but long-term exposure above the federal limit can cause bone disease and tooth mottling.
- **Nitrate** — A compound from fertilizer runoff, septic systems, and erosion of natural deposits. Levels above the federal limit can cause 'blue baby syndrome,' a serious oxygen-transport condition in infants.
- **Sulfate** — A naturally occurring mineral from rock and soil. No health-based federal limit; high levels can have a laxative effect and a bitter taste.
- **Chromium, Hexavalent** — Hexavalent chromium ('chromium-6') — the more toxic form of chromium. A known carcinogen by inhalation; regulated nationally only within the total-chromium limit, with stricter limits in some states.
- **Copper** — A metal that enters water from corroding household plumbing. Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.
- **Iron** — A naturally occurring metal common in groundwater. Regulated only as a secondary (cosmetic) standard; causes rusty color, staining, and metallic taste.
- **Lead** — A toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. There is no safe level of lead; it harms brain development in children and raises blood pressure in adults. The EPA sets an action level, not a health goal above zero.
- **Sodium** — A naturally occurring salt component. Not federally regulated for health; relevant for people on sodium-restricted diets.
- **Escherichia coli (E. coli)** — Escherichia coli — bacteria found in the gut of humans and animals. Its presence in drinking water indicates fecal contamination and a real risk of waterborne illness.
- **Perfluorohexanesulfonic acid** — Perfluorohexanesulfonic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Perfluorohexanoic acid** — Perfluorohexanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and widely detected.
- **Perfluoropentanoic acid** — Perfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **PFOS** — Perfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **Hardness** — A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
- **Specific Conductance** — A measure of how well water conducts electricity, which tracks dissolved mineral content. Not federally regulated for health; used as a proxy for total dissolved solids.
- **Total Dissolved Solids** — Total dissolved solids — the combined content of all dissolved minerals and salts. Regulated only as a secondary (cosmetic) standard; high levels affect taste and hardness.
- **Turbidity** — A measure of cloudiness from suspended particles in the water. High turbidity can shelter microbes from disinfection; the EPA enforces it through a treatment-technique standard.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **Uranium** — A naturally occurring radioactive metal from erosion of natural deposits. Long-term exposure above the federal limit can damage the kidneys and increase cancer risk.
- **Tetrachloroethylene** — An industrial solvent (PCE) used in dry cleaning and degreasing. A likely human carcinogen; long-term exposure above the federal limit can damage the liver and kidneys.
- **Trichloroethylene** — An industrial solvent (TCE) used in metal degreasing. A known human carcinogen; long-term exposure above the federal limit can damage the liver.

## How to read this

- A water-quality report covers an entire service area, not a single address.
- 'Federal limit' is the EPA standard (MCL, action level, treatment technique, etc.) that the measured level is compared against.
- 'At or above the federal limit' means the utility's own reported figure met or exceeded that standard.

_Figures are the utility's own published numbers. Generated 2026-05-25 from thewatermap.com._