Houston Tap Water Quality: What’s Really in Your Drinking Water?
Quick Summary: Houston’s tap water meets federal safety standards, but reports from the Environmental Working Group (EWG) and the city’s 2024 Consumer Confidence Report reveal measurable levels of contaminants such as arsenic, Chromium-6, disinfection byproducts (TTHMs and HAA5), PFAS compounds, and trace radiological materials. These substances, though within EPA limits, exceed EWG’s health-based guidelines and may contribute to long-term health risks including cardiovascular disease, skin irritation, and certain cancers.
When most people in Houston pour a glass of tap water, they assume it’s safe to drink. After all, the Texas Commission on Environmental Quality (TCEQ) and Houston Public Works both say the city’s water meets federal requirements for safe drinking water.
But “meeting standards” doesn’t always mean “ideal.” Recent reports from the Environmental Working Group (EWG), along with Houston’s own Consumer Confidence Report, show the city’s drinking water contains several inorganic contaminants, disinfection byproducts, and unregulated chemicals that can impact human health with long-term exposure.
Let’s take a closer look at Houston’s water supplies, what’s in your tap, and how homeowners are taking extra precautions to protect their families.
Where Houston’s Water Comes From
Houston’s water supply is drawn primarily from:
- Lake Houston, fed by the San Jacinto River
- Trinity River watershed
- Chicot and Evangeline Aquifers (for supplemental groundwater)
This complex system blends surface water and groundwater, both of which pick up natural deposits of minerals and inorganic contaminants like arsenic and Chromium (hexavalent), better known as Chromium-6.
The city treats water at several municipal water treatment plants, then distributes it through thousands of miles of pipelines. While this ensures safety against pathogens, the chemical disinfection process can also create byproducts like Total Trihalomethanes (TTHMs) and Haloacetic acids (HAA5).
What’s in Houston’s Tap Water?
According to Houston’s 2024 Consumer Confidence Report and the EWG Tap Water Database, several harmful contaminants have been detected in small but measurable amounts across the city. These include:
- Arsenic (Average Detection: ~0.7 ppb): Naturally occurring in Texas’ sediment and Chicot Aquifers.
- Exposure to arsenic over time is associated with cardiovascular disease, colon cancer, skin lesions, and circulatory damage.
- The goal for arsenic levels, according to the EWG Health Guideline, is 0.004 ppb, though the federal limit (the EPA’s Maximum Contaminant Level) is 10 ppb.
- Houston’s levels remain below the federal standard, but well above the ideal goal for human health.
- Chromium-6 (Hexavalent Chromium): A toxic metal in its natural form that can enter water from natural deposits or industrial runoff.
- The EWG Health Guideline recommends 0.02 ppb, while some Houston testing shows average detection levels between 0.3–0.8 ppb.
- Long-term level arsenic exposure or chromium ingestion can increase risks for kidney damage, skin irritation, and certain cancers.
- Disinfection Byproducts (TTHMs and HAA5): Formed when chlorine reacts with organic matter during treatment.
- Houston’s average detection for Total Trihalomethanes ranges between 40–60 µg/L, near the EPA limit of 80 µg/L.
- Haloacetic acids (HAA5), including Bromochloroacetic acid, average 20–30 µg/L, just below the federal threshold of 60 µg/L.
- Health effects: Studies link prolonged exposure to higher levels of these compounds with increased risks of colon cancer, liver problems, and reproductive issues.
- PFAS Compounds (Forever Chemicals): The EWG has identified Perfluorobutanoic acid (PFBA), Perfluoropentanoic acid (PFPeA), and Perfluorohexanoic acid (PFHxA) in Houston’s tap water at trace levels.
- These unregulated contaminants are under review by the U.S. EPA Enforcement and Compliance History Database and can accumulate in the body over time, potentially leading to immune suppression, thyroid disruption, and developmental effects.
- Radiological Contaminants: Trace amounts of radium-226 and uranium have been found in some Houston water supplies, primarily due to natural deposits. While levels meet federal regulations, they add to the complex water chemistry of the region.
Health Effects of Houston’s Water Contaminants
Most of Houston’s tap water is considered safe to drink under EPA standards, but long-term exposure to low levels of multiple contaminants can still affect human health.
Potential health effects linked to Houston’s detected contaminants include:
- Skin lesions and irritation from arsenic and disinfection byproducts
- Cardiovascular disease from inorganic contaminants and long-term mineral exposure
- Kidney disease and circulatory damage from Chromium-6 and arsenic
- Cancer risk, particularly colon cancer, associated with TTHMs, HAA5, and PFAS compounds
Environmental Factors and Water Quality Challenges
Houston’s water system faces unique challenges due to its geography and history.
- Hurricane Harvey and other major storms have disturbed sediment layers, exposing Superfund sites near the San Jacinto River. These sites contain industrial waste and can leach trace inorganic contaminants into local waterways.
- Rapid urban development and the influx of people coming to the Texas Medical Center and surrounding neighborhoods put added stress on water treatment infrastructure.
- Houston Public Works continues to monitor the Safety of Houston’s water through its Drinking Water Operations Division. Their Houston Water Safe to Drink update provides transparency about ongoing testing and federal compliance.
Still, the EWG and independent water filter labs recommend taking extra precautions, especially for vulnerable groups like children, pregnant women, or people with existing health effects from chronic exposure.
Improving Water Quality at Home
Culligan of Dallas has helped North Texas homeowners for decades with custom water treatment solutions built to handle local mineral content and chemical treatment challenges.
Our systems start with a free water quality test and are tailored to your home’s water chemistry, plumbing layout, and household size.
Water Softener Systems
Culligan’s water softeners use a salt-based ion exchange system to remove calcium and magnesium, replacing them with sodium ions. This process softens your water, protects your plumbing, and restores comfort to your showers and laundry.
Benefits include:
- Less scale buildup on fixtures
- Longer-lasting water heaters and dishwashers
- Softer skin and smoother hair
- Cleaner laundry and dishes
- Reduced appliance maintenance
Filtration for Added Protection
Dallas homeowners also turn to whole-home filtration systems and under-sink reverse osmosis units for added protection against chlorine taste, organic materials, and trace contaminants.
Culligan’s carbon filtration systems and reverse osmosis (RO) systems target both minerals and chemical impurities, delivering clean, great-tasting drinking water straight from your tap.
At-Home Testing
A professional Culligan Water Quality Test provides accurate readings of levels in water, including arsenic, chlorine, PFAS, and TDS. Unlike a basic water pitcher filter, Culligan systems address a full range of harmful contaminants to meet or exceed federal requirements for safe drinking water.
Final Takeaway
Houston’s drinking water meets federal safety standards, but it still contains trace levels of arsenic, Chromium-6, Haloacetic acids, Total Trihalomethanes, and PFAS compounds. While these contaminants are below legal limits, the ideal goal for many of them, according to the EWG Health Guideline, is zero.
For added peace of mind, many residents are turning to Culligan’s Houston Water Solutions, including Reverse Osmosis and Activated Carbon systems, to reduce exposure to arsenic and other harmful contaminants while improving water taste and overall quality.
Want to know exactly what’s in your Houston tap water?
Schedule a free in-home Water Quality Test today and learn how Culligan of Houston can help protect your home and your health.
