An Introduction to LT2

In January 2006, the federal Environmental Protection Agency (EPA) issued a new drinking water rule under the Safe Drinking Water Act called the Long Term 2 Enhanced Surface Water Treatment Rule (LT2).

According to the EPA, “The purpose of the LT2 rule is to reduce illness linked with the contaminant Cryptosporidium and other disease-causing microorganisms in drinking water.” Cryptosporidium is a micro-organism (protozoan) naturally present in bodies of surface water throughout the world. Surface water supplies are particularly vulnerable if they regularly receive runoff or pollution from human or animal wastes.

The LT2 rule impacts two separate parts of Portland’s water system by requiring that the City:

• Provide additional treatment for its Bull Run supply to either remove or inactivate Cryptosporidium.

• End the use of the open finished drinking water reservoirs  at Mt. Tabor and Washington parks.

The EPA deadline for construction of a treatment facility to comply with the treatment portion of the LT2 rule is April 1, 2014. The deadline for compliance with the open reservoir portion of the rule is December 31, 2015 for the Mt. Tabor Reservoirs and December 31, 2020 for the Washington Park Reservoirs.

For more information, contact Terry Black, Portland Water Bureau, at  (503) 823-1168.