# San Antonio, TX — Drinking Water Quality (2023)

> Contaminant levels for the San Antonio, TX public water system from its 2023 Consumer Confidence Report, compared to federal limits.

- Page: https://www.thewatermap.com/water/tx/san-antonio/2023
- JSON API: https://www.thewatermap.com/api/water/tx/san-antonio/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: 16
- Contaminants with a federal limit: 16
- 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 | 1.47 mg/L (Average) | System-wide | 4 mg/L (MRDL) | Within the limit |
| HAA5 | Disinfection byproducts | 0–19.4 ug/L (Range) | Range of Individual Samples | 60 ug/L (MCL) | Within the limit |
| TTHM | Disinfection byproducts | 0–52.9 ug/L (Range) | Range of Individual Samples | 80 ug/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.15–3.31 mg/L (Range) | Concentration Range Found | 4 mg/L (MCLG) | Approaching the limit |
| Nitrate | Inorganic chemicals | 0–2.51 mg/L (Range) | Concentration Range Found | 10 mg/L (MCLG) | Within the limit |
| Barium | Metals | 0.0945 mg/L (Reported level) | System-wide | 2 mg/L (MCLG) | Within the limit |
| Copper | Metals | 0.206 mg/L (90th percentile) | At the tap | 1.3 mg/L (MCLG) | Within the limit |
| Lead | Metals | 2.25 ug/L (90th percentile) | At the tap | 0 ug/L (MCLG) | Detected — no federal limit |
| Lithium | Metals | 12.82 ug/L (Average) | System-wide | 9 ug/L (MCL) | At or above the limit |
| Selenium | Metals | 4.2 ug/L (Reported level) | System-wide | 50 ug/L (MCLG) | Within the limit |
| Total Coliform | Microbial | 0.5 (Highest single sample) | No. of Positive | 0 (MCLG) | Detected — no federal limit |
| Perfluoropentanoic acid | PFAS ("forever chemicals") | 0.0032 ug/L (Average) | System-wide | 0.003 ug/L (MCL) | At or above the limit |
| PFBA | PFAS ("forever chemicals") | 0.0075 ug/L (Average) | System-wide | 0.005 ug/L (MCL) | At or above the limit |
| Combined Radium | Radionuclides | 1.33–1.82 pCi/L (Range) | Concentration Range Found | 0 pCi/L (MCLG) | Detected — no federal limit |
| Gross Alpha | Radionuclides | 6.2 pCi/L (Reported level) | System-wide | 0 pCi/L (MCLG) | Detected — no federal limit |
| Gross Beta Particle Activity | Radionuclides | 0–5.5 pCi/L (Range) | Concentration Range Found | 0 pCi/L (MCLG) | Detected — no federal 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.
- **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.
- **Barium** — A metal from erosion of natural deposits and industrial discharge. Long-term exposure above the federal limit can raise blood pressure.
- **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.
- **Lithium** — A naturally occurring element found in some groundwater. No enforceable federal limit; on the EPA contaminant candidate list for further study.
- **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.
- **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.
- **Perfluoropentanoic acid** — Perfluoropentanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment.
- **PFBA** — Perfluorobutanoic acid, a shorter-chain PFAS 'forever chemical.' Monitored under EPA rules; persistent in the environment and the human body.
- **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.
- **Gross Beta Particle Activity** — Gross beta particle activity — a combined measure of beta-emitting radioactive substances. Long-term exposure above the federal screening level increases cancer risk.

## 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 2026-05-25 from thewatermap.com._