# Monrovia-city, Water Dept. — Monrovia, Ca, CA — Drinking Water Quality (2021)

> Contaminant levels for the Monrovia-city, Water Dept. — Monrovia, Ca, CA public water system from its 2021 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/monrovia-city-water-dept-monrovia-ca/2021
- JSON API: https://www.thewatermap.com/api/water/ca/monrovia-city-water-dept-monrovia-ca/2021
- 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: 2021
- Contaminants measured: 16
- Contaminants with a federal limit: 11
- Contaminants at or above the federal limit: 2
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 0.94 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| HAA5 | Disinfection byproducts | Not detected ug/L (Average) | System-wide | No federal limit | None detected |
| TTHM | Disinfection byproducts | 15.15 ug/L (Average) | System-wide | No federal limit | Within the limit |
| Fluoride | Inorganic chemicals | 0.39 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 3.61 mg/L (Average) | System-wide | 10 mg/L (MCL) | Within the limit |
| Copper | Metals | 0.14 mg/L (90th percentile) | At the tap | 1.3 mg/L (Action level) | Within the limit |
| Lead | Metals | Not detected ug/L (90th percentile) | At the tap | No federal limit | Within the limit |
| Escherichia coli (E. coli) | Microbial | 0 % (Highest single sample) | System-wide | No federal limit | None detected |
| Total Coliform | Microbial | 1.96 % (Highest single sample) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoroheptanoic acid | PFAS ("forever chemicals") | 2.47 ng/L (Average) | System-wide | 4 ng/L (NL) | Detected — no federal limit |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | 3.24 ng/L (Average) | System-wide | 3 ng/L (NL) | Within the limit |
| Perfluorohexanoic acid | PFAS ("forever chemicals") | 25.57 ng/L (Average) | System-wide | 4 ng/L (NL) | Detected — no federal limit |
| PFOA | PFAS ("forever chemicals") | 5.38 ng/L (Average) | System-wide | 5.1 ng/L (NL) | At or above the limit |
| PFOS | PFAS ("forever chemicals") | 9.78 ng/L (Average) | System-wide | 6.5 ng/L (NL) | At or above the limit |
| Gross Alpha | Radionuclides | 1.5 pCi/L (Average) | System-wide | 15 pCi/L (MCL) | Within the limit |
| Trichloroethylene | VOCs & pesticides | 0.3 ug/L (Average) | System-wide | 5 ug/L (MCL) | Within 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.
- **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.
- **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.
- **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.
- **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.
- **Total Coliform** — A group of bacteria used as an indicator of overall water-system sanitation. Coliforms themselves are usually harmless, but their presence signals that disease-causing organisms could enter the system.
- **Perfluoroheptanoic acid** — Perfluoroheptanoic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **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.
- **PFOA** — Perfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
- **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.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **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 2026-06-04 from thewatermap.com._