# Marin Municipal Water District — Corte Madera, Ca, CA — Drinking Water Quality (2021)

> Contaminant levels for the Marin Municipal Water District — Corte Madera, Ca, CA public water system from its 2021 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/ca/marin-municipal-water-district-corte-madera-ca/2021
- JSON API: https://www.thewatermap.com/api/water/ca/marin-municipal-water-district-corte-madera-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: 13
- Contaminants with a federal limit: 8
- Contaminants at or above the federal limit: 0
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chloramine | Disinfectants | 1.71 mg/L (Average) | System-wide | 4 mg/L (MRDLG) | Within the limit |
| HAA5 | Disinfection byproducts | 26 ug/L (Average) | Site Average | No federal limit | Within the limit |
| TTHM | Disinfection byproducts | 63 ug/L (Average) | Site Average | No federal limit | Within the limit |
| Bromide | Inorganic chemicals | 31 ug/L (Average) | Reservoir Water | No federal limit | Detected — no federal limit |
| Fluoride | Inorganic chemicals | 0.71 mg/L (Average) | System-wide | 0.6 mg/L (Treatment technique) | Within the limit |
| Nitrate | Inorganic chemicals | Not detected mg/L (Average) | System-wide | 10 mg/L (Public health goal) | Within the limit |
| Copper | Metals | 0.13 mg/L (90th percentile) | At the tap | 0.3 mg/L (Public health goal) | Within the limit |
| Lead | Metals | Not detected ug/L (90th percentile) | At the tap | 0.2 ug/L (Public health goal) | None detected |
| Manganese | Metals | 2.8 ug/L (Average) | Reservoir Water | 500 ug/L (NL) | Detected — no federal limit |
| Total Coliform | Microbial | 1.2 % (Maximum) | Monthly | 0 % (MCLG) | Detected — no federal limit |
| pH | Physical & aggregate | 8.1 (Average) | System-wide | No federal limit | Detected — no federal limit |
| TOC | Physical & aggregate | 2.9 mg/L (Average) | Reservoir Water | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 0.11 NTU (Reported level) | System-wide | 1 NTU (Treatment technique) | Within the limit |

## What these contaminants are

- **Chloramine** — A longer-lasting disinfectant made by combining chlorine with ammonia. Holds disinfection further into the pipe network, but is regulated under the same residual-disinfectant cap as chlorine.
- **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.
- **Bromide** — A naturally occurring salt found in source water. Not directly regulated, but a precursor that increases formation of brominated disinfection byproducts.
- **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.
- **Manganese** — A naturally occurring metal from soil and rock. No enforceable federal limit; high levels stain fixtures and laundry and can affect taste, with a health advisory for infants.
- **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.
- **pH** — A measure of how acidic or basic the water is. Regulated only as a secondary standard; very low or high pH can corrode pipes or affect taste.
- **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.

## 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._