# Houston, TX — Drinking Water Quality (2023)

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

- Page: https://www.thewatermap.com/water/tx/houston/2023
- JSON API: https://www.thewatermap.com/api/water/tx/houston/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: 23
- Contaminants with a federal limit: 20
- 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 | 3 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Chlorine | Disinfectants | 1.7 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Chlorite | Disinfection byproducts | 0.002 mg/L (Average) | System-wide | 1 mg/L (MCL) | Within the limit |
| HAA5 | Disinfection byproducts | 39 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| TTHM | Disinfection byproducts | 45 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Cyanide | Inorganic chemicals | 52.5 ug/L (Average) | System-wide | 200 ug/L (MCL) | Within the limit |
| Fluoride | Inorganic chemicals | 0.21 mg/L (Average) | System-wide | 4 mg/L (MCL) | Within the limit |
| Nitrate | Inorganic chemicals | 0.39 mg/L (Average) | System-wide | 10 mg/L (MCL) | Within the limit |
| Nitrite | Inorganic chemicals | 0.03 mg/L (Average) | System-wide | 1 mg/L (MCL) | Within the limit |
| Arsenic | Metals | 2.2 ug/L (Average) | System-wide | 10 ug/L (MCL) | Within the limit |
| Barium | Metals | 0.3 mg/L (Average) | System-wide | 2 mg/L (MCL) | Within the limit |
| Copper | Metals | 0.37 mg/L (Average) | System-wide | 90 mg/L (Action level) | Within the limit |
| Lead | Metals | 7.8 ug/L (Average) | System-wide | 90 ug/L (Action level) | Within the limit |
| Lithium | Metals | 23.8 ug/L (Average) | System-wide | No federal limit | Detected — no federal limit |
| Selenium | Metals | 1.8 ug/L (Average) | System-wide | 50 ug/L (MCL) | Within the limit |
| Total Coliform | Microbial | 4.5 (Average) | System-wide | 5 (MCL) | Approaching the limit |
| Combined Radium | Radionuclides | 1.77 pCi/L (Average) | System-wide | 5 pCi/L (MCL) | Within the limit |
| Gross Alpha | Radionuclides | 7 pCi/L (Average) | System-wide | 15 pCi/L (MCL) | Within the limit |
| Gross Beta Particle Activity | Radionuclides | 5.6 pCi/L (Average) | System-wide | 50 pCi/L (MCL) | Within the limit |
| Uranium | Radionuclides | 3.4 ug/L (Average) | System-wide | 30 ug/L (MCL) | Within the limit |
| Atrazine | VOCs & pesticides | 0.1 ug/L (Average) | System-wide | 3 ug/L (MCL) | Within the limit |
| Simazine | VOCs & pesticides | 0.03 ug/L (Average) | System-wide | 4 ug/L (MCL) | Within the limit |
| Xylenes | VOCs & pesticides | 0.4 ug/L (Average) | System-wide | 10 ug/L (MCL) | 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.
- **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.
- **Nitrite** — A compound from fertilizer runoff, sewage, and erosion of natural deposits. Like nitrate, elevated levels can cause 'blue baby syndrome' in infants.
- **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.
- **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.
- **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.
- **Uranium** — A naturally occurring radioactive metal from erosion of natural deposits. Long-term exposure above the federal limit can damage the kidneys and increase 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.
- **Xylenes** — A group of industrial solvents found in gasoline and paint. Long-term exposure above the federal limit can damage the nervous system.

## 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._