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

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

- Page: https://www.thewatermap.com/water/ca/eureka-eureka-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/eureka-eureka-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: 15
- Contaminants with a federal limit: 4
- Contaminants at or above the federal limit: 1
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 0.17–0.49 mg/L (Reported level) | System-wide | 4 mg/L (MCL) | Within the limit |
| HAA5 | Disinfection byproducts | 3.7–7.4 ug/L (Reported level) | System-wide | No federal limit | Within the limit |
| TTHM | Disinfection byproducts | 9.5–18 ug/L (Reported level) | System-wide | No federal limit | Within the limit |
| Chloride | Inorganic chemicals | 3.9 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Fluoride | Inorganic chemicals | 0.46–0.56 mg/L (Reported level) | System-wide | No federal limit | Within the limit |
| Sulfate | Inorganic chemicals | 10 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Aluminum | Metals | 0.011 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Copper | Metals | 90 ug/L (Reported level) | System-wide | 1700 ug/L (Public health goal) | Within the limit |
| Lead | Metals | 90 ug/L (Reported level) | System-wide | 2 ug/L (Public health goal) | At or above the limit |
| Sodium | Metals | 3.7 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Hardness | Physical & aggregate | 67–83 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| pH | Physical & aggregate | 7.2–7.5 (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Specific Conductance | Physical & aggregate | 140–182 uS/cm (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Total Dissolved Solids | Physical & aggregate | 90 mg/L (Reported level) | System-wide | No federal limit | Detected — no federal limit |
| Turbidity | Physical & aggregate | 0.02–0.08 NTU (Reported level) | System-wide | 1 NTU (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.
- **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.
- **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.
- **Aluminum** — A common element sometimes used as a treatment coagulant. Regulated only as a secondary (cosmetic) standard; high levels can discolor water.
- **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.
- **Sodium** — A naturally occurring salt component. Not federally regulated for health; relevant for people on sodium-restricted diets.
- **Hardness** — A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
- **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.
- **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.

## 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._