Water Reuse

Drinking Water Regulations

Summaries of major EPA regulations related to microbial contaminants

Total Coliform Rule - 1989, (currently under revision)
The Total Coliform Rule (TCR) attempts to provide public health protection from all microbial contaminants, not just coliforms. This is possible because it uses coliform presence as an indicator of water quality. This rule applies to all PWSs and is the only regulation that attempts to ensure water safety throughout the PWS's distribution system (most rules require only monitoring at the entry point to the distribution system). The number of samples a system is required to take to ensure compliance varies based on system size, and presence of coliforms in over 5% (for systems with over 40 samples per month) constitutes a violation of this rule. Fecal coliforms and E.coli are also specifically monitored under this rule.

Surface Water Treatment Rule - 1989
Interim Enhanced Surface Water Treatment Rule - 1998
Long Term 1 Enhanced Surface Water Treatment Rule - 2002
Long Term 2 Enhanced Surface Water Treatment Rule - 2006
These rules were created in order to protect against microbes such as Cryptosporidium, Giardia Lambia, Legionella and viruses. The original SWTR required filtering and disinfection for all PWSs that used surface water or surface water under the influence of groundwater as their source. PWSs are also required to monitor disinfection residual entering the distribution system. The revised versions of this rule also contain regulations about turbidity requirements, finished water reservoirs, and more specific requirements about monitoring and eliminating certain microbes.

Stage 1 Disinfection and Disinfection Byproducts Rule - 1998
Stage 2 Disinfection and Disinfection Byproducts Rule - 2006
The disinfection byproducts rules protect public health by regulating dangerous chemicals that result from common disinfection practices at drinking water treatment facilities. These rules establish and strengthen MCLs for common disinfectants and potent disinfection byproducts such as trihalomethanes and haloacetic acids. In addition, they also establish certain requirements for disinfection byproduct precursors (as measured by total organic carbon concentration) in the water before it is disinfected. This rule applies to all public water systems.

Groundwater Rule - 2006
The Groundwater rule was established to recognize that while groundwater sources of drinking water tend to be safer than surface water in terms of microbial contamination, there are still some risks. This rule applies to systems with groundwater sources only. The rule requires routine sanitary surveys that inspect the entire PWS, corrective action for problems identified during this process, increased source water monitoring based on total coliform rule violations, and regulations about inactivation or removal of viruses.

Drinking Water Distribution Systems: Assessing and Reducing Risks. National Research Council. The National Academies Press, Washington, DC. 2006.