Verified utility-level summary
Public drinking water can meet federal standards while still exceeding other health-based guidelines. The comparisons below clearly identify whether a number is an EPA legal limit or an EWG health guideline.
City snapshot
Utility represented: City of Houston
EWG data period: 2013–2024
Utility
City of Houston
Water source
Surface water
Above EWG guidelines
14
Total detected
51
An EWG health guideline is a health-based benchmark, not an EPA legal limit. Public drinking water can meet federal standards while exceeding other health-based guidelines.
Detected: 2.06 ppb
516×
EWG health guideline
Arsenic can occur naturally in groundwater and may also enter water from industrial or agricultural sources.
The EWG health guideline and EPA legal limit are different benchmarks. The detected level shown here is below the listed EPA legal limit while exceeding EWG's health-based guideline.
Detected: 6.19 ppb
103×
EWG health guideline
This treatment byproduct can form when disinfectants react with naturally occurring material in source water.
EWG publishes a health-based guideline for this individual disinfection byproduct. No individual EPA legal limit is shown for it here.
Detected: 0.155 ppm
Approximately 1.1×
EWG health guideline
Nitrate can enter source water from fertilizer, wastewater, septic systems, and natural deposits.
The detected level shown is below the EPA legal limit while slightly exceeding EWG's health-based guideline.
Treatment depends on the specific water concern and your home. These technologies address different needs.
Helps address hardness minerals and scale. A softener does not remove every contaminant listed in a utility report.
May help reduce chlorine, chloramine, and certain treatment byproducts or other contaminants where supported.
Provides additional drinking-water treatment and may reduce many dissolved contaminants.
Published utility data describes the public water system, not a test of the water at your specific faucet. Water quality can vary by utility, neighborhood, plumbing and over time.
Methodology and disclaimer: Detected values and summary counts on this page come from the supplied Environmental Working Group Tap Water Database record for the represented utility. EWG health guidelines are health-based benchmarks and are not EPA legal limits. Treatment information is educational and does not guarantee performance for a specific home.
Primary data source: Environmental Working Group Tap Water Database