Drinking Water Rules
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 (2005)
Surface Water Treatment Rule (1989) As the name suggests, this Rule applies to all public water systems whose source is either surface water or groundwater under the direct influence of surface water. Most of the nation’s large water systems draw from surface sources like rivers, lakes, and reservoirs, which are particularly susceptible to microbial contamination. The Rule requires 99.9 percent protection from Giardia cysts, and 99.99 percent protection from viruses. To meet these requirements, most sources must be treated through a combination of disinfection and filtration.
Giardia lamblia and Legionella
Two microbes are specifically addressed in the Rule. Giardia is a parasite that causes severe dehydration, diarrhea, and nausea. Legionnaires' Disease is a type of pneumonia caused by inhaling airborne Legionella bacteria. The Rule sets maximum contaminant level goals (MCLGs) for these pathogens at zero because any exposure constitutes a health risk. At the same time, an exact count of these microbes is not as important as making sure they are destroyed, so in this case, the MCL is replaced by a Treatment Technique for Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, and turbidity.
For more information about this rule visit the EPA webpage:
http://www.epa.gov/OGWDW/therule.html#Surface
Interim Enhanced Surface Water Treatment Rule
After the initial Surface Water Treatment Rule was enacted, EPA studies found that certain microbes are resistant to traditional disinfection practices. This rule is designed to improve the reliability of water treatment and filtering in public water systems. In addition, the rule requires disinfection benchmarks be established so facilities can assure continued levels of microbial protection while taking necessary steps to comply with new disinfection byproducts standards.
Cryptosporidium
In 1993, Cryptosporidium caused 400,000 people in Wisconsin to become ill, more than 4,000 of those were hospitalized, and at least 50 deaths have been attributed to the disease. This rule specifically addresses Cryptosporidium as well as risk trade-offs with disinfection byproducts.
For more information about this rule, visit the EPA webpage:
http://www.epa.gov/OGWDW/mdbp/qrg_ieswtr.pdf
Long Term 1 Enhanced Surface Water Treatment Rule (2002)
While the Interim Enhanced Surface Water Treatment Rule only applies to systems serving 10,000 or more people, this rule includes to small systems, those serving fewer than 10,000 people. It also requires systems to calculate levels of microbial inactivation to make sure that protection is not jeopardized when systems make changes to comply with requirements of the Stage 1 Disinfectants and Disinfection Byproducts Rule (Stage 1-DBPR).
For more information about this rule, visit the EPA webpage:
http://www.epa.gov/OGWDW/mdbp/lt1eswtr-quick-ref.pdf
Long Term 2 Enhanced Surface Water Treatment Rule (2006)
This latest revision of the Surface Water Treatment Rule is designed to further strengthen existing regulations and provide a higher level of protection of your drinking water supply by requiring Cryptosporidium treatment in high risk systems, improving protection for uncovered finished water reservoirs, ensure that systems maintain microbial protection as they take steps to reduce the formation of disinfection byproducts
For more information about this rule, visit the EPA webpage:
http://www.epa.gov/safewater/disinfection/lt2/pdfs/qrg_lt2_qrg_sch1_final.pdf
Every six years the EPA is required to review its standards for drinking water regulation. With additional surveillance and improved technology, water is further protected every year. While regulations, monitoring, and reporting requirements change regularly, our staff at Neilson Research Corporation can assist you with any questions you may have.
