Texas is home to thousands of rivers, lakes, creeks, reservoirs, and coastal waterways. Unfortunately, water-quality monitoring has found elevated bacteria levels in waterways across much of the state.
The Texas Commission on Environmental Quality has identified bacteria-impaired waterways in counties throughout Texas, including major population centers such as Dallas, Tarrant, Collin, Harris, Travis, Bexar, and Denton counties. Elevated bacteria can make swimming or wading more hazardous, particularly after heavy rain or wastewater-related incidents.
That sounds alarming, but an important distinction often gets lost: bacteria in a river or lake does not automatically mean bacteria are present in treated tap water.
Public drinking-water systems treat source water, disinfect it, monitor the distribution network, and test for microbial contamination. Understanding that process can help Texans respond appropriately without assuming every local water-quality report means their faucet is unsafe.
What Are Fecal Bacteria?
Fecal bacteria are microorganisms associated with human and animal waste.
Water-quality programs frequently test for indicator bacteria instead of trying to identify every possible disease-causing organism. In Texas freshwater, Escherichia coli, commonly called E. coli, is often used as an indicator of fecal contamination.
Most strains of E. coli are not harmful. However, finding E. coli in water suggests that human or animal waste may have entered the source. That waste could also contain viruses, parasites, or harmful bacteria.
Total coliform bacteria serve a different purpose. They are found throughout the environment and do not necessarily indicate fecal contamination. Their presence in treated drinking water may signal a weakness in treatment, storage, plumbing, or the distribution system that requires investigation.
How Does Fecal Bacteria Enter Waterways?
Bacteria can enter Texas waterways through several sources:
- Leaking sewer lines or wastewater overflows
- Failing septic systems
- Livestock and agricultural operations
- Wildlife and bird waste
- Pet waste left on lawns, sidewalks, or trails
- Stormwater runoff
- Flooding that carries waste into rivers and reservoirs
Heavy rainfall can make the problem worse. Runoff moving across streets, farms, yards, and animal habitats can collect bacteria before entering storm drains and nearby waterways.
Unlike household wastewater, stormwater may reach a creek or lake without first passing through a wastewater-treatment plant.
What Happens Before Water Reaches Your Tap?
A bacteria-impaired creek or lake is not the same as contaminated tap water. Some impaired waterways are evaluated primarily for recreational activities and may not supply drinking water at all.
When surface water is used as a drinking-water source, it normally passes through several protective steps:
- Coagulation and sedimentation help remove suspended particles.
- Filtration captures smaller particles and microorganisms.
- Disinfection inactivates bacteria, viruses, and other microbes.
- Distribution monitoring helps protect water as it travels to customers.
The exact process varies by water source and utility. Public systems also maintain a disinfectant residual to provide continued microbial protection as water moves through tanks, pumps, and pipes.
Problems can still occur after treatment. Broken water mains, low pressure, cross-connections, equipment failures, storage-tank vulnerabilities, or contamination during repairs can affect the distribution system.
How Is Drinking Water Tested for E. Coli?
Public water systems collect routine samples from designated locations throughout their distribution networks.
The first test generally looks for total coliform bacteria. A total-coliform-positive result does not automatically confirm fecal contamination. It signals that the system needs additional testing.
In Texas, a public water system that receives a positive routine result must generally collect three repeat samples within 24 hours:
- One from the original location
- One upstream within five service connections
- One downstream within five service connections
Samples that test positive for total coliform are also analyzed for E. coli. Groundwater systems may need to test wells that were operating when the positive sample was collected.
An E. coli-positive result is more serious because it indicates that human or animal waste may have entered the system. Certain combinations of positive routine and repeat samples create an E. coli maximum contaminant level violation requiring rapid state and public notification.
Why Is a Boil-Water Notice Issued?
A boil-water notice means water in the distribution system may be unsafe for consumption or may pose an acute health risk.
Confirmed E. coli contamination is one possible reason, but a notice may also be issued because of:
- Loss of water pressure
- A major water-main break
- A prolonged service outage
- Treatment or filtration failure
- Inadequate disinfection
- Excessive turbidity
- Flooding or another event that may compromise the system
A notice is often precautionary. It does not always mean officials have confirmed harmful bacteria. It means the system cannot currently guarantee that the water meets normal safety requirements.
What Should Residents Do During a Notice?
Always follow instructions from your local water provider or public-health authority.
During a boil-water notice, use commercially bottled or properly boiled water for drinking, cooking, brushing teeth, making ice, washing produce, preparing infant formula, and giving water to pets. Discard ice made with tap water during the notice.
Reverse osmosis provides an important additional barrier against many contaminants, and RO membranes can reject microorganisms based on their size. However, a boil-water notice may indicate broader problems involving water pressure, damaged infrastructure, cross-connections, or contamination within the distribution system.
A household purifier should therefore complement official precautions, not replace them.
Continue following the boil-water notice even if your water passes through a purifier or looks, smells, and tastes normal. NECOA’s hot-water setting should also not be treated as a substitute for the rolling boil required by emergency guidance.
For additional emergency-water guidance, explore our Houston Hurricane Preparedness Guide and review the CDC’s drinking-water advisory recommendations.
How Is the Problem Corrected?
Depending on the cause, a water system may:
- Collect repeat and source-water samples
- Repair damaged pipes, pumps, or treatment equipment
- Restore normal pressure
- Flush and disinfect affected lines
- Inspect wells, tanks, and distribution infrastructure
- Correct cross-connections or other sanitary defects
- Conduct additional testing
- Notify regulators and affected customers
A notice is not lifted simply because repairs are complete. The utility must perform the required corrective actions and testing before announcing that normal water use may resume.
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How NECOA Supports Better Water at Home
Municipal treatment provides essential protection, but water can still encounter aging infrastructure, household plumbing, and trace contaminants before reaching the glass.
NECOA Smart Water Purifiers provide an additional point-of-use treatment step after water enters the home. NECOA Pro models use 3-filter, 5-stage reverse osmosis purification, while Icon models use Nano-Trap filtration technology.
Available features include automatic UV care, smart filter monitoring, precise dispensing, and hot, cold, or ambient purified water, depending on the model.
Under normal operating conditions, NECOA can help filter more than 80 contaminants and provide a convenient source of purified water for drinking, cooking, and filling reusable emergency-storage containers. Automatic filter delivery and ongoing maintenance through Free-Flow Service+ also help ensure the system continues operating as intended.
During a boil-water notice, continue following local instructions. After the notice is lifted, follow utility and manufacturer guidance for flushing plumbing, connected appliances, and the purifier before returning to normal use.
Learn more about how reverse osmosis addresses other water-quality concerns in The Truth About Minerals in Water and Arsenic in Groundwater.
Fecal bacteria in Texas waterways are a legitimate concern, particularly for swimming and other direct-contact activities. However, an impaired waterway and a contaminated household tap are not the same thing.
Public treatment provides the first line of protection. NECOA adds another layer at the point of use, helping Texas households take greater control over the quality, convenience, and consistency of their everyday drinking water.
Explore NECOA Smart Water Purifiers Today
Sources
- Texas Commission on Environmental Quality, Texas Counties with Bacteria-Impaired Water Bodies
- Texas Commission on Environmental Quality, Understanding Boil-Water Notices
- Texas Commission on Environmental Quality, Responding to a Total-Coliform-Positive Sample
- Centers for Disease Control and Prevention, Drinking-Water Advisories