Ozone and Bromate in Drinking Water
Public water systems that use ozone in the treatment of drinking water must comply with the maximum contaminant level for bromate, monitoring, and sampling requirements.
On this page:
- Ozone and the Disinfection Byproduct Bromate
- Maximum Contaminant Level - Bromate
- Monitoring, Sampling, and Analysis
- Health Effects
- Reporting Requirements
- Consumer Notification
- Assistance and Tools for Public Water Systems
Ozone and the Disinfection Byproduct Bromate
Ozone can be used in the treatment of drinking water to improve taste, odor, and color, remove iron and manganese, and inactivate chlorine resistant microorganisms. Public water systems (PWS) may choose to use ozone because it is less likely to form disinfection byproducts (DBPs) than free chlorine.
Bromate is a DBP that can form when ozone is used to treat water containing bromide. All community and non-transient, non-community PWSs that use ozone must monitor for bromate.
Monitoring, Analyzing, and Reporting Bromate for PWS Using Ozone (RG-544) - Additional details about requirements and procedures for monitoring, analysis, reporting, and complying with bromate rules can be found in the regulatory guidance.
Maximum Contaminant Level - Bromate
PWS must adhere to requirements for the maximum contaminant level (MCL). Compliance for bromate is determined based on a running annual average (RAA) of monthly averages, calculated quarterly. If the RAA exceeds 0.010 mg/L MCL, this is a MCL violation and the PWS must notify customers as soon as possible but no later than 30 days after the violation is identified.
Monitoring, Sampling, and Analysis
PWS are responsible for collecting bromate samples; collection of samples must be performed by a licensed water operator.
- Make sure your monitoring plan is up to date with the frequency and locations of bromate sample sites.
- PWS Monitoring Plans and Lab Approval - Information about monitoring plan requirements.
- Environmental Laboratory (NELAP) Accreditation - Find a NELAP accredited laboratory to analyze your bromate samples.
| Number Samples | Frequency | Sampling Location | Monitor For | Sample Analysis By |
| 1 | Monthly | Entry Point | Bromate | Accredited |
Health Effects
An exceedance of bromate is not an emergency. However, some people who drink water containing bromate in excess of the MCL over many years may have an increased risk of getting cancer.
Reporting Requirements
The PWS must submit laboratory analysis results for bromate to TCEQ by the 10th day of the month following the monitoring period by mail.
Consumer Notification
Public Notice Language for Drinking Water Compliance – If your PWS has a MCL or monitoring and reporting violation, you can find required language and certificate of delivery documents organized by contaminant to use for public notification.
Consumer Confidence Report - Community water systems must provide the minimum, maximum, and average levels of any contaminant detected in their annual Consumer Confidence Report to customers by July 1 of each year. A community water system supplies water to the same population year-round.
Texas Drinking Water Viewer - Find sample results and monitoring schedules.
Assistance and Tools for Public Water Systems
Contact TCEQ at DBP@tceq.texas.gov or 512-239-1062 if you have questions about the bromate RAA. Find sample schedules and sample results on Texas Drinking Water Viewer.
EPA Stage 2 Disinfectants and Disinfection Byproducts Rule Operational Evaluation Guidance Manual - Information about specific factors that influence DBP formation and ways to control formation can be found in this EPA guidance.
Financial, Managerial and Technical Assistance - TCEQ offers FREE financial, managerial, and technical (FMT) assistance to help PWSs comply with regulations. Contact FMT for help with issues such as, but not limited to preventing operational problems, training about how to comply with rule requirements and performing capacity assessments.
Technical Guidance for Public Water System Operators and Engineers - Information about technical questions, such as submitting plans, exploring treatment options, or requesting exceptions to design or capacity rules.