Houston tap water is legally safe to drink. The city’s water meets all federal EPA standards and is tested regularly by Houston Public Works and the Texas Commission on Environmental Quality. That’s the official answer, and it holds up.
But independent analysis tells a more detailed story. According to the Environmental Working Group’s Tap Water Database, Houston’s water contains a number of contaminants — including chromium-6, arsenic, PFAS, and disinfection byproducts — that exceed health-based guidelines even when they fall within the legal limit. Add in Houston’s notoriously hard water and the legacy of industrial contamination from storm events near the San Jacinto River, and you have a water quality picture that’s more complex than “passes the test.”
This guide covers what’s actually in Houston tap water, which filtration systems address which concerns, and what installation looks like for homeowners in the greater Houston area.
What’s in Houston Tap Water
Houston’s water comes primarily from surface water sources — Lake Houston, Lake Conroe, and Lake Livingston — supplemented by the Chicot and Evangeline aquifer systems. Each source brings its own contaminant profile, and the city’s industrial history and storm vulnerability add additional complexity.
Hard Water Minerals
Houston’s water is hard. Calcium and magnesium concentrations are high enough that scale deposits are a daily reality for Houston homeowners — on faucets and showerheads, inside appliances, and inside the pipes themselves. Hard water reduces the efficiency and lifespan of water heaters, dishwashers, and washing machines. It’s also why Houston households deal with soap scum, spotted glassware, dry skin and hair, and that familiar white crust on fixtures.
The effect on plumbing is cumulative and expensive over time. Scale buildup inside a water heater is one of the primary drivers of premature unit failure in Houston — the same sediment problem covered in our water heater replacement post applies here. Hard water isn’t a health concern, but its impact on your home’s plumbing and appliances is real.
Chlorine and Disinfection Byproducts
Houston disinfects its water supply with chlorine. Chlorine is effective at killing pathogens, but it reacts with naturally occurring organic matter in source water to form disinfection byproducts — primarily trihalomethanes (TTHMs) and haloacetic acids (HAA5). Both are present in Houston’s water at levels that meet federal standards but exceed EWG’s more protective health-based guidelines.
Long-term exposure to elevated disinfection byproducts has been associated with increased cancer risk, particularly bladder cancer. For most healthy adults the risk at Houston’s levels is low, but it’s a legitimate reason many households choose to filter their drinking water. Standard activated carbon filtration removes chlorine and significantly reduces disinfection byproducts.
Chromium-6 (Hexavalent Chromium)
Chromium-6 is a known carcinogen that enters water from natural deposits and industrial sources. Houston’s tap water has tested at levels that, while below the federal enforcement limit, significantly exceed EWG’s health guideline. One analysis found Houston’s chromium-6 levels averaging approximately 35 times above the concentration associated with negligible cancer risk.
This is one of the more concerning contaminants in Houston’s water from a long-term health perspective. Reverse osmosis is the most effective at-home solution for chromium-6 removal.
PFAS (“Forever Chemicals”)
PFAS — per- and polyfluoroalkyl substances — are synthetic chemicals that persist indefinitely in the environment and accumulate in the human body. They’ve been linked to cancer, hormone disruption, and immune effects. PFAS have been detected in Houston’s water supply, with the Houston area among the Texas systems where PFAS concentrations have been identified. Federal PFAS limits took effect in 2024, and water utilities are under active pressure to reduce levels.
Elevated PFAS concentrations have been particularly associated with areas near the San Jacinto River, where industrial Superfund sites have been a documented contamination source. Houston homeowners who want to address PFAS should look for reverse osmosis systems or whole-house filters certified specifically for PFAS removal.
Arsenic
Arsenic enters Houston’s water naturally from Texas’s sediment and aquifer geology. Houston’s levels are below the federal limit of 10 parts per billion, but they consistently exceed EWG’s health guideline of 0.004 ppb. Arsenic is a known carcinogen linked to skin, bladder, and lung cancer with long-term exposure. Reverse osmosis removes arsenic effectively at the point of use.
Lead from Household Plumbing
Houston’s municipal water supply is treated to minimize lead, but lead can still enter drinking water by leaching from older household pipes, solder, and fixtures. About 10 percent of lead samples tested in Houston have exceeded 4 parts per billion. If your home was built before 1986, older plumbing is a meaningful risk factor. A point-of-use filter certified for lead removal — or a whole-home system with lead reduction capability — is the practical solution.
Industrial and Storm Runoff Contaminants
Houston’s industrial history and repeated major storm events create a contamination risk that most other major cities don’t face to the same degree. The San Jacinto River Waste Pits Superfund site has been a documented source of dioxin and other industrial contaminants entering local waterways. Hurricane Harvey’s 2017 flooding disturbed contaminated sediment across industrial zones and created widespread water quality concerns that persisted for months afterward. These aren’t constant, daily risks — but they’re part of Houston’s specific water quality context in a way that makes proactive filtration a more reasonable precaution than it might be elsewhere.
Aqueduct Plumbing installs water filtration and softening systems throughout Houston. Call us to discuss which system is right for your home.
Water Filtration Options for Houston Homeowners
Houston’s water quality concerns span both the mineral and contaminant categories, which means there’s no single system that addresses everything. Here’s what each option does — and what it doesn’t.
Whole-House Water Softeners
A water softener uses ion exchange to replace the calcium and magnesium that cause hardness with sodium ions, delivering soft water to every tap, appliance, and fixture in the home.
What it addresses: Hard water scale, appliance wear, dry skin and hair, soap scum, spotted dishes. It also reduces the sediment buildup that shortens water heater lifespans in Houston.
What it doesn’t address: Chlorine taste and odor, disinfection byproducts, PFAS, chromium-6, arsenic, or lead. A softener is a hardness solution, not a contaminant filter.
Texas does not have the same softener discharge restrictions found in parts of California. Salt-based ion exchange softeners are widely used across the Houston area without the regulatory complications that apply in some other states.
Whole-House Carbon Filtration
A whole-house carbon filter installs on the main water line and treats all water entering the home. Carbon media adsorbs chlorine, reduces disinfection byproducts, and removes many volatile organic compounds and some pesticides, improving taste and odor at every tap and in every shower.
What it addresses: Chlorine taste and odor, disinfection byproducts (TTHMs and HAA5), VOCs, some herbicides.
What it doesn’t address: Hard water minerals, PFAS (standard carbon — some catalytic carbons have limited PFAS reduction), arsenic, chromium-6, or lead. Carbon filtration is a meaningful improvement for taste and some health concerns, but not comprehensive coverage for Houston’s full contaminant profile.
Reverse Osmosis Systems
Reverse osmosis forces water through a semi-permeable membrane that removes dissolved solids, heavy metals, PFAS, arsenic, chromium-6, nitrates, lead, and a wide range of other contaminants. For Houston’s specific contaminant profile — chromium-6, arsenic, PFAS, and lead risk from older plumbing — RO is the most effective at-home drinking water solution available.
Most residential RO systems are under-sink, point-of-use units serving the kitchen tap. Whole-house RO exists but is expensive and generally unnecessary unless there’s a specific reason to treat all water in the home to that standard.
What it addresses: PFAS, chromium-6, arsenic, lead, nitrates, dissolved solids, and most contaminants of health concern in Houston’s water.
What to know: RO systems produce some wastewater as part of the filtration process and filter more slowly than unfiltered tap flow, which is why most include a storage tank under the sink. Filters and membranes require periodic replacement. A licensed plumber installs the system by tapping into the existing cold water supply line.
Softener + RO Combination
For Houston homeowners who want comprehensive coverage — soft water throughout the home and filtered drinking water at the tap — a whole-house water softener paired with an under-sink RO unit is the most complete solution available. The softener handles scale protection for appliances, plumbing, and comfort; the RO handles drinking water quality.
This combination addresses the full range of Houston’s water quality concerns and is the most common setup Aqueduct installs for homeowners who want both problems solved in a single project.
Not sure which system fits your home and water quality concerns? Aqueduct Plumbing serves Houston homeowners with licensed installation of water softeners, filtration systems, and reverse osmosis.