Haloacetic Acids (HAA5)

Disinfection byproducts (DBPs) are chemicals that form, during drinking water treatment and distribution, when naturally occurring organic matter reacts with chlorine or other disinfectants used to kill pathogenic organisms. The EPA has determined that Haloacetic Acids (HAA5) are one of the chemical classes that must be monitored. 
The Texas Commission on Environmental Quality (TCEQ) uses contract samplers to collect all HAA5 samples used for compliance. HAA5 samples are analyzed by the Lower Colorado River Authority or the Department of State Health Services and results are provided to the city and published online at TCEQ's Drinking Water Watch page. To read more about disinfection byproducts, visit TCEQ's webpage on DPBs.
Data is updated quarterly as sample results are received.

HAA5 Results

To comply with the Stage 2 Disinfection Byproduct Rule, the rolling quarterly average for HAA5 at each sample site must be below .060 mg/L (60 ug/L).

To view sample results at each location, click "View Source Data" below the chart.

HAA5 Chlorine Maintenance Special Samples

The North Texas Municipal Water District conducts chlorine maintenance throughout the water delivery system in March each year. Starting in 2018, the City of Plano began collecting samples to analyze disinfection byproducts during this time period. Samples are collected from the same 12 sites normally sampled plus the four pump stations. In 2019, special sampling was conducted twice during the maintenance period. The chart below shows the HAA5 special sample results by location. The chart below shows the HAA5 special sample results by location from both sample dates.