Stage 2 Disinfectant By-Products  
With the next round of drinking water regulations coming out, the water industry will have to be on alert. Upcoming regulatory requirements include a Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR), the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Ground Water Rule. Implementation schedules for some of the regulations are very tight, so utilities will not be able to depend on state assistance to get started on required monitoring.

The Stage 2 DBPR will supplement existing drinking water regulations with risk-targeted monitoring and compliance determinations for current disinfection byproduct maximum contaminant levels (MCL). This regulation will apply to all systems that add a disinfectant other than ultraviolet light. The rule requires each utility to conduct a year-long Initial Distribution System Evaluation (IDSE) to identify locations with high DBP concentrations. These locations will then be used as sampling sites for DBP compliance monitoring. The monitoring requirements of the IDSE must be initiated within six months of the rule being finalized. A report identifying the new compliance sites must be delivered to the state in two years.

Stage 2 DBPR leaves utilities limited time to decide how to perform the IDSE study, initiate and complete monitoring, and file its report.

 In addition to the monitoring for the IDSE, utilities serving more than 10,000 people using surface water will be required to begin monitoring their plant influent for Cryptosporidium within six months of the rule being finalized. After two years of monitoring for Cryptosporidium, plants must use the resulting data to determine the required level of additional treatment.

Plants that use groundwater or a mixture of surface and ground water will be affected by the requirements of the Ground Water Rule.

The proposed Ground Water Rule establishes multiple barriers to protect against bacteria and viruses from ground water sources. The rule will specify when corrective action is required.

All ground water systems that disinfect will be required to monitor their disinfection process. For systems that chlorinate their water before it goes into the distribution system, the rule requires that a specified contact time be maintained between the disinfectant and the water prior to its reaching the first customer.
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