# St. Helena, City of — St. Helena, Ca, CA — Drinking Water Quality (2023)

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

- Page: https://www.thewatermap.com/water/ca/st-helena-st-helena-ca/2023
- JSON API: https://www.thewatermap.com/api/water/ca/st-helena-st-helena-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: 6
- Contaminants with a federal limit: 2
- Contaminants at or above the federal limit: 3
- Part of The Water Map — https://www.thewatermap.com

## Contaminants measured

| Contaminant | Category | Measured level | Sampling context | Federal limit | Status |
|---|---|---|---|---|---|
| Chlorine | Disinfectants | 0.93 mg/L (Average) | System-wide | No federal limit | Within the limit |
| HAA5 | Disinfection byproducts | 61.71 ug/L (Average) | System-wide | No federal limit | At or above the limit |
| TTHM | Disinfection byproducts | 64.76 ug/L (Average) | System-wide | No federal limit | Approaching the limit |
| Fluoride | Inorganic chemicals | 0.11 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Barium | Metals | 40 mg/L (Average) | System-wide | 2 mg/L (MCL) | At or above the limit |
| Turbidity | Physical & aggregate | 4.6 NTU (Reported level) | System-wide | No federal limit | At or above 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.
- **Barium** — A metal from erosion of natural deposits and industrial discharge. Long-term exposure above the federal limit can raise blood pressure.
- **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._