# Montara Water and Sanitary District — Montara, Ca, CA — Drinking Water Quality (2023)

> Contaminant levels for the Montara Water and Sanitary District — Montara, Ca, CA public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/montara-water-and-sanitary-district-montara-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/montara-water-and-sanitary-district-montara-ca/2023
- 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: 2023
- Contaminants measured: 19
- Contaminants with a federal limit: 12
- Contaminants at or above the federal limit: 4
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| HAA5 | Disinfection byproducts | 2.4–12 ug/L (Range) | System-wide | No federal limit | Within the limit |
| TTHM | Disinfection byproducts | 13–36 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Dibromoacetic acid | Inorganic chemicals | 2.4–6.7 ug/L (Range) | System-wide | 0.03 ug/L (Public health goal) | Within the limit |
| Dichloroacetic acid | Inorganic chemicals | 0–2.8 ug/L (Range) | System-wide | 0.2 ug/L (Public health goal) | Within the limit |
| Fluoride | Inorganic chemicals | 0.29–0.34 mg/L (Range) | System-wide | 4 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 0–7.4 mg/L (Range) | System-wide | 10 mg/L (MCL) | Within the limit |
| Trichloroacetic acid | Inorganic chemicals | 0–2.3 ug/L (Range) | System-wide | 0.1 ug/L (Public health goal) | Within the limit |
| Arsenic | Metals | 0–7.3 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Copper | Metals | 0.15 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 | None detected |
| Escherichia coli (E. coli) | Microbial | 0 (Maximum) | No. of detections | 0 (MCLG) | None detected |
| Total Coliform | Microbial | 0 (Maximum) | No. of detections | 0 (MCLG) | None detected |
| Perfluorobutanesulfonic acid | PFAS ("forever chemicals") | 0–4 ng/L (Range) | System-wide | 500 ng/L (NL) | Detected — no federal limit |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | 0–47 ng/L (Range) | System-wide | 3 ng/L (NL) | At or above the limit |
| PFOA | PFAS ("forever chemicals") | 0–9.8 ng/L (Range) | System-wide | No federal limit | At or above the limit |
| PFOS | PFAS ("forever chemicals") | 0–6 ng/L (Range) | System-wide | 6.5 ng/L (NL) | At or above the limit |
| TOC | Physical & aggregate | 0.51–0.71 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 1 NTU (Reported level) | System-wide | No federal limit | At or above the limit |
| Combined Radium | Radionuclides | 0–0.12 pCi/L (Range) | System-wide | 5 pCi/L (MCL) | Within the limit |

## What these contaminants are

- **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.
- **Dibromoacetic acid** — A brominated haloacetic acid disinfection byproduct. Part of the broader HAA9 group; monitored without its own enforceable limit.
- **Dichloroacetic acid** — A haloacetic acid disinfection byproduct. One of the five haloacetic acids regulated together as HAA5 for 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.
- **Trichloroacetic acid** — A haloacetic acid disinfection byproduct. One of the five haloacetic acids regulated together as HAA5.
- **Arsenic** — A naturally occurring element that also enters water from industry and agriculture. A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
- **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.
- **Perfluorobutanesulfonic acid** — Perfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.' Has no standalone limit but is part of the EPA PFAS Hazard Index that limits PFAS in combination.
- **Perfluorohexanesulfonic acid** — Perfluorohexanesulfonic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **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.
- **TOC** — Total organic carbon — a measure of organic material dissolved in the water. Not harmful itself, but it is the raw material that forms disinfection byproducts; removal is a treatment requirement.
- **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.
- **Combined Radium** — Combined radium-226 and radium-228 — naturally occurring radioactive elements. Long-term exposure above the federal limit increases the risk of bone cancer.

## 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._