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Bromate Monitoring

Monitoring Schedules

Find current bromate monitoring schedules.

Bromate monitoring applies to community and non-transient non-community systems using ozone as a disinfectant or oxidant. Bromate is a disinfectant byproduct that is formed when ozone is used as a disinfectant in the presence of bromide, which is a naturally occurring element found in ground and surface water sources. Some people who drink water containing bromate in excess of the MCL over many years may have an increased risk of getting cancer.

Bromate Monitoring for Systems Using Ozone
Routine Monitoring Reduced Monitoring
1 Sample per Month 1 Sample per Quarter

Note: Systems required to analyze for bromate may reduce monitoring from monthly to once per quarter, if the system demonstrates that the running annual average bromate concentration is less than or equal to 0.0025 mg/L based upon routine monthly bromate measurements for the most recent four quarters. In addition, the samples must be analyzed using Method 317.0 Revision 2.0, 326.0, or 321.8.

Sample Site
Sampling should occur at the entry point to the distribution system.

Maximum Contaminant Level (MCL)
The MCL for bromate is 0.010 mg/L. Compliance with the MCL is based on a running annual average. A running annual average is the arithmetic average of results and is calculated at the end of every quarter. Systems must continue to compute the RAA quarterly after qualifying for reduced bromate monitoring and, if the RAA exceeds 0.0025 mg/L, the system must return to monthly monitoring.