# Mendota, City of — Mendota, Ca, CA — Drinking Water Quality (2023)

> Contaminant levels for the Mendota, City of — Mendota, Ca, CA public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/mendota-mendota-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/mendota-mendota-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: 43
- Contaminants with a federal limit: 7
- Contaminants at or above the federal limit: 7
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| HAA5 | Disinfection byproducts | 4.8–14 ug/L (Range) | System-wide | No federal limit | Within the limit |
| TTHM | Disinfection byproducts | 28–82 ug/L (Range) | System-wide | No federal limit | At or above the limit |
| Fluoride | Inorganic chemicals | 0.4–0.64 mg/L (Range) | System-wide | 4 mg/L (MCL) | Within the limit |
| Arsenic | Metals | 0–6.7 mg/L (Range) | System-wide | No federal limit | At or above the limit |
| Calcium | Metals | 70–100 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Chromium, Hexavalent | Metals | 0.05–1 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Copper | Metals | Not detected mg/L (90th percentile) | At the tap | 1.3 mg/L (Action level) | None detected |
| Lead | Metals | Not detected ug/L (90th percentile) | At the tap | No federal limit | Within the limit |
| Potassium | Metals | 2.2 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Selenium | Metals | 5–50 ug/L (Range) | System-wide | No federal limit | At or above the limit |
| Escherichia coli (E. coli) | Microbial | 0 (Highest single sample) | No. of Detections | 0 (MCLG) | None detected |
| Total Coliform | Microbial | 0 (Highest single sample) | No. of Detections | No federal limit | None detected |
| Alachlor | Other | 1 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Chlorine Total | Other | 0.06–2.46 mg/L (Range) | System-wide | 4 mg/L (MCL) | Within the limit |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | PFAS ("forever chemicals") | 0–0.005 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| 9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS) | PFAS ("forever chemicals") | 0.00215 ug/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Hexafluoropropylene oxide dimer acid | PFAS ("forever chemicals") | 0–0.005 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Nonafluoro-3,6-dioxaheptanoic acid | PFAS ("forever chemicals") | 0–0.02 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | PFAS ("forever chemicals") | 0–0.004 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorobutanesulfonic acid | PFAS ("forever chemicals") | 0.00345 ug/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorodecanoic acid (PFDA) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorododecanoic acid (PFDoA) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoroheptanesulfonic acid (PFHpS) | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoroheptanoic acid | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorohexanesulfonic acid | PFAS ("forever chemicals") | 0.0058 ug/L (Reported level) | System-wide | No federal limit | Within the limit |
| Perfluorohexanoic acid | PFAS ("forever chemicals") | 0–0.003 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluorononanoic acid | PFAS ("forever chemicals") | 0–0.004 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Perfluoropentanesulfonic acid (PFPeS) | PFAS ("forever chemicals") | 0–0.004 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoropentanoic acid | PFAS ("forever chemicals") | 0.0035 ug/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Perfluoroundecanoic acid (PFUnA) | PFAS ("forever chemicals") | 0.00215 ug/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| PFBA | PFAS ("forever chemicals") | 0–0.005 ug/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| PFOA | PFAS ("forever chemicals") | 0–0.004 ug/L (Range) | System-wide | No federal limit | At or above the limit |
| PFOS | PFAS ("forever chemicals") | 0–0.004 ug/L (Range) | System-wide | No federal limit | At or above the limit |
| Bicarbonate | Physical & aggregate | 20–1000 mg/L (Range) | System-wide | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 1–5 ug/L (Range) | System-wide | 5 ug/L (MCL) | Detected — no federal limit |
| Combined Radium | Radionuclides | 0–1.1 pCi/L (Range) | System-wide | 5 pCi/L (MCL) | Within the limit |
| Gross Alpha | Radionuclides | 0–6.07 (Range) | System-wide | 15 (MCL) | Detected — no federal limit |
| Atrazine | VOCs & pesticides | 0.5–1 ug/L (Range) | System-wide | No federal limit | Within the limit |
| Benzene | VOCs & pesticides | 82–130 ug/L (Range) | System-wide | No federal limit | At or above the limit |
| Simazine | VOCs & pesticides | 0.004–4 ug/L (Range) | System-wide | No federal limit | At or above 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.
- **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.
- **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.
- **Calcium** — A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and 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.
- **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.
- **Potassium** — A naturally occurring mineral from rock and soil. Not federally regulated for health.
- **Selenium** — A trace element from natural deposits and industrial discharge. Essential in tiny amounts, but long-term exposure above the federal limit can cause hair and fingernail loss and circulatory problems.
- **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.
- **11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)** — 11-chloroeicosafluoro-3-oxaundecane-1-sulfonic acid, a chlorinated PFAS compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **4,8-Dioxa-3H-perfluorononanoic acid (ADONA)** — ADONA, a newer-generation PFAS replacement compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **9-Chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9Cl-PF3ONS)** — 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid, a chlorinated PFAS compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Hexafluoropropylene oxide dimer acid** — HFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Nonafluoro-3,6-dioxaheptanoic acid** — Nonafluoro-3,6-dioxaheptanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro-3-methoxypropanoic acid (PFMPA)** — Perfluoro-3-methoxypropanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro-4-methoxybutanoic acid (PFMBA)** — Perfluoro-4-methoxybutanoic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **Perfluoro(2-ethoxyethane)sulfonic acid (PFEESA)** — Perfluoro(2-ethoxyethane)sulfonic acid, a PFAS-related compound. Monitored under EPA rules as part of broad PFAS surveillance.
- **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.
- **Perfluorodecanoic acid (PFDA)** — Perfluorodecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluorododecanoic acid (PFDoA)** — Perfluorododecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **Perfluoroheptanesulfonic acid (PFHpS)** — Perfluoroheptanesulfonic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **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.
- **Perfluorononanoic acid** — Perfluorononanoic acid, a PFAS 'forever chemical.' Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
- **Perfluoropentanesulfonic acid (PFPeS)** — Perfluoropentanesulfonic acid, a PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluoropentanoic acid** — Perfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **Perfluoroundecanoic acid (PFUnA)** — Perfluoroundecanoic acid, a longer-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent and bioaccumulative.
- **PFBA** — Perfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment and the human body.
- **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.
- **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.
- **Gross Alpha** — Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
- **Atrazine** — A widely used agricultural herbicide that reaches water through runoff. Long-term exposure above the federal limit can affect the cardiovascular and reproductive systems.

## 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._