Water Quality in Houston

High levels of contamination and reduced availability highlight growing concerns for the Houston-area water supply

Amidst growing populations, the quality of our water supply remains an issue in need of attention throughout our region.

Why water quality matters to Houston

Texas and the Houston area have vast water resources including a great number of major rivers and streams running across the state. These water resources support both natural ecosystems and human habitation. In highly developed urban areas like the Houston region, urban waterways take on concentrated pollution from industrial discharges, vehicles, residential and commercial wastewater, trash and polluted stormwater runoff, posing health threats for residents and the environments they live in.1 To ensure a healthy ecosystem that protects humans, plants, and animals, the quality of water in the Houston area must be closely monitored and defended.

And the more we understand the issues affecting water quality in the Houston area, the more we can do to protect this essential resource for future generations.

The data

Overall water supply has increased, but not enough to keep up with population growth

Water supply in the Houston region is increasing while freshwater sources are limited. While the Houston region has a good supply of water, as the population grows across the region, only responsible water usage will ensure the preservation of this vital natural resource.

For both Harris and Fort Bend counties, the annual public supply of water by total withdrawals increased from 2010 to 2015. (“Withdrawals” refers to water taken from the ground or surface for use in homes, businesses, industries and food production.)

“The public water supply per capita decreased for all three counties between 2010 to 2015.”

High violation levels threaten the safety of Houston’s drinking water

Ensuring safe drinking water can help to prevent illness, birth defects and even death.2 To ensure the water is safe for human consumption, public water systems are frequently checked to verify that the levels of contaminants present in the water do not exceed the Maximum Contaminant Levels set by the EPA.3

As of July 1, 2019, Texas regulates 7,020 public water systems, providing drinking water to more than 28 million customers.3

According to the Safe Drinking Water Information System (SDWIS) federal reporting system, Harris County had a total of 1,330 drinking water violations reported from its 1,228 active  facilities in 2018. It had the most drinking water violations among the three counties, but it is difficult to determine the exact population impacted by each violation. Fort Bend and Montgomery counties have fewer public water systems operating in the area and water violations reported. Additionally, not all violations are equivalent; testing date, frequency and location can also affect the detection and severity of violations.

Contamination levels

The presence of coliform bacteria, such as E.Coli, in the water system, indicates that water supplies are contaminated by human or animal wastes. Most E.Coli bacteria are harmless. However, some strains can cause serious illness and pose higher risks for infants and young children, so the levels of E.Coli are often used as an indicator for fecal contamination. For example, the levels of E.Coli bacteria were above normal after Hurricane Harvey.4

Non-coliform bacteria also cause health problems if ingested. For example, organic chemicals may impact cardiovascular systems, cause reproductive problems, problems with blood, nervous system, liver problems, and increase cancer risk.5 Inorganic chemicals like arsenic and lead can cause skin damage, problems with circulatory systems and increase cancer risk, as well as delays in physical and mental development  in children.5

According to TCEQ records, among 62,971 coliform samples collected in Harris County in 2018, only 150 samples, or 0.24%, contained a presence of coliform bacteria. Among the 150 samples, 16 samples (11%) contained a presence of E.Coli bacteria.

Of 24,289 non-coliform samples collected in Harris County, 1,835 had non-coliform analytes over the specified limit for the given compound, that’s 7.6% of all samples taken. Non-coliform samples indicated a high level of inorganic chemicals like Nitrates (15.7%) and Arsenic (1.9%); organic compounds like Atrazine (3.5%); and Radionuclide compounds (about 1%).6

How waste management contributes to water pollution

While waste management is essential to resource conservation, some practices can result in waste and toxic materials being released by industrial facilities into the water. According to the EPA, the preferred management method is recycling, followed by energy recovery, treatment, and at last disposing or releasing the waste to the environment.

The Toxic Release Inventory (TRI), an EPA program that provides data on toxic chemical releases and pollution prevention, ranks Texas as the 24th out of the 56 states/territories based on total releases per square miles, with 1st meaning the highest releases. The amount of production-related waste managed in Texas declined from 4.3 billion pounds in 2003 to 4 billion pounds in 2017, accounting for 13% of the total production-related waste managed in the country.

Not in line with EPA preferences, Texas typically relies on treatment rather than recycling. Only 21% of waste was recycled in Texas, compared to the national average of 48%.

However, trends and practices vary throughout the three-county area. On average, 25% of waste was recycled. Although the amount of industrial waste in Fort Bend County is the lowest among the three counties, it disposed or released 30% of production-related waste, more than double the national average, and six times greater than the state average. Additionally, merely 0.3% of production-related waste was recycled in Fort Bend County. In contrast, Harris County accounted for 30% of the total industrial waste managed in the state, and it largely mirrors the state trends in terms of waste management methods. In 2017, 1.4 million pounds of TRI-covered chemicals, or about 5% of on-site releases were to the water in Harris County. Fort Bend and Montgomery counties had only 1,800 thousand pounds and 104 pounds of on-site releases of TRI-covered chemicals to the water respectively, accounting for less than 0.1% of total on-site releases. Montgomery County relies on waste treatment at a much higher rate than the rest of the region and only 12% of the waste was recycled and another 10% was released or disposed into the environment. However, it is notable that in Montgomery County, carcinogenic chemicals such as nickel and lead were found in on-site releases to the water.

Contamination impacts the majority of area water sources

Ground and surface refer to the naturally occurring water sources beneath and above the Earth’s surface, respectively. While 75% of the groundwater in Texas is used for agricultural purposes, mostly for irrigation, the Houston region also relies on groundwater for domestic and industrial usage.7

When a water source becomes polluted or otherwise contaminated, it is considered to be impaired. In heavily populated areas like Houston, the most common contaminants of groundwater come from petroleum storage tank facilities.8

Overall, 60% of the water streams found in the three-county area are currently impaired due to bacterial contamination, making their water unsafe for consumption. Some of the most commonly found factors for bacterial contamination are malfunctioning wastewater treatment plants, sanitary sewer system overflows, failing onsite sewer facilities and septic systems, etc.

Harris County has the most miles of impaired streams, about 515 miles in total, compared to 279 miles in Montgomery County and 105 in Fort Bend County. As a percentage of all miles of streams, Harris County has the highest proportion of contaminated streams (71%), compared to 52% in Montgomery County and 43% in Fort Bend County.

Trash Bash cleanup results

Another important source of contamination of our groundwater comes from litter and trash thrown in the waterways. To raise awareness and address the issue, the Houston-Galveston Area Council gathers volunteers from across the Houston area to conduct a one-day clean-up of major waterways in the area during the annual “Trash Bash”. While there is not a way to measure all the trash that ends up in our waterways, data collected during “Trash Bash” offers a snapshot of how we’re doing.

The volume of trash collected has gone down over the past decade. In 2019, 4,290 volunteers collected 56.6 tons of trash along 153 miles of shoreline, compared to more than 200 tons collected by 4,830 volunteers in 2001.



  1. U.S. Environmental Protection Agency. “Why Urban Waters,” last modified February 23, 2017.
  2. Craun, Gunther F., et al. “Causes of outbreaks associated with drinking water in the United States from 1971 to 2006.” Clinical Microbiology Reviews 23, no. 3 (2010): 507-528.
  3. Texas Commission on Environmental Quality. 2018 Public Drinking Water Annual Compliance Report. 2019. Web.
  4. Rice Kinder Institute for Urban Research, “E. coli Levels Up (Way Up) After Harvey,” last modified September 21, 2017.
  5. U.S. Environmental Protection Agency. National Primary Drinking Water Regulation Table. 2016. Web.
  6. Texas Commission on Environmental Quality. “Harris County Drinking Water Quality – Non-Coliform Analytes – 2014-2018 (data set),” Rice Kinder Institute: Urban Data Platform (2018).
  7. Lesikar, Bruce J., and Valeen Silvy. “Questions about Groundwater Conservation Districts in Texas.” Texas A&M AgriLife Extension Service (2008).
  8. Texas Groundwater Protection Committee, “Groundwater Contamination,” State of Texas.