City of Lewisville

This report summarizes the quality of municipal water that the City of Lewisville provides to our residents. The information includes data compiled during 2017 from the latest U.S. Environmental Protection Agency (EPA) required testing. It also covers what our water contained, its sources, treatment methods, and general contamination concerns.

Lewisville's water system has earned a "Superior" rating—the highest ranking awarded by the Texas Commission on Environmental Quality. To ensure safety, the EPA establishes regulations limiting contaminant amounts in public water systems, while FDA sets similar standards for bottled water to provide equivalent public health protection.

When municipal water meets federal standards, there may be no health benefits to purchasing bottled water or point-of-service filtration systems. All water sources, including bottled water, naturally contain small amounts of certain contaminants. The presence of these substances doesn't necessarily indicate a health risk. For more information about contaminants and potential health effects, call the EPA's Safe Drinking Water Hotline at 800.426.4791.

Some populations may be more vulnerable to certain microbial contaminants in water and should consult their healthcare providers. These include infants, elderly individuals, immunocompromised persons (such as cancer patients undergoing chemotherapy, organ transplant recipients, people on steroid treatment, and those with HIV/AIDS), who may face increased infection risks.

Since 1998, Lewisville has monitored for Cryptosporidium, a microbial parasite commonly found in surface water that can come from animal and human waste. Importantly, Cryptosporidium has never been detected in either untreated or treated water supplies. For guidelines on reducing infection risk, contact the Safe Drinking Water Hotline at 800.426.4791.

Where Our Water Comes From

Our municipal water is pumped from Lake Lewisville, our surface water source, to our Water Treatment Plant for processing before distribution. We also purchase treated water from Dallas Water Utilities when needed.

Water sources include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over land or underground, it dissolves natural minerals and sometimes radioactive materials, and may pick up substances from animal or human activity.

Potential contaminants in source water before treatment include:

• Microbial contaminants (viruses, bacteria) from sewage treatment plants, septic systems, agricultural operations, and wildlife
• Inorganic contaminants (salts, metals) that occur naturally or result from urban runoff, wastewater discharges, oil/gas production, mining, or farming
• Pesticides and herbicides from agriculture, urban runoff, and residential uses
• Organic chemical contaminants, including synthetic and volatile organic compounds from industrial processes, petroleum production, gas stations, runoff, and septic systems
• Radioactive contaminants occurring naturally or resulting from oil/gas production and mining

You may notice taste, color, or odor issues in your water that aren't health concerns. For questions about water aesthetics, contact Dallas Water Utilities at 214.670.0915.

The Texas Commission on Environmental Quality is updating a Source Water Susceptibility Assessment for our water sources. This information describes potential contamination risks based on human activities and natural conditions. For details, visit Drinking Water Watch at http://bit.ly/2IYQ5ct or the Source Water Assessment Viewer at http://bit.ly/2IIwjPa.

Lead and Copper Information

Elevated lead levels can cause serious health problems, especially for pregnant women and young children. Lead in tap water primarily comes from materials in service lines and home plumbing. While we provide high-quality water, we can't control plumbing component materials. If your water has been sitting for several hours, you can minimize lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for consumption. For concerns about lead, consider water testing. Information about lead in water, testing methods, and exposure reduction is available from the Safe Drinking Water Hotline or at epa.gov/safewater/lead.

Water Treatment Process

Our treatment process removes contaminants including sand, minerals, suspended particles, organic matter, microorganisms, viruses, and synthetic chemicals. As untreated water enters our facility, we add chlorine, ammonia, and seasonally, carbon to address taste and odor issues.

We use coagulation and flocculation with ferric sulfate and polymer to remove turbidity and color. Lime adjusts pH as particles form floc that settles and is removed. Clarified water passes through filters to eliminate remaining suspended particles, then undergoes disinfection before storage in tanks that allow chemical mixing throughout the water supply.

From storage, water enters the distribution network through pipe systems serving the entire city. Elevated storage tanks provide additional capacity and system pressure. Our Water Production Plant can produce 20 million gallons of treated water daily, meeting all state and federal quality requirements.

.. ...