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Washington Aqueduct Water Quality

The quality of the water being produced at Washington Aqueduct is excellent. It meets or exceeds all United States Environmental Protection Agency (US EPA) standards and requirements.

Recent improvements in coagulation and filtration have enabled Washington Aqueduct to keep its filtered water turbidity at less than 0.1 NTU (Nephelometric Turbidity Unit). This is much lower than the US EPA standard of 0.3 NTU. This extremely low turbidity provides excellent barrier against pathogens such as Cryptosporidium and Giardia.

Our disinfection system is designed to keep the water safe in our wholesale customers' distribution systems all the way to the consumer. Our conversion to chloramines as a secondary disinfectant in the fall of 2000 has worked extremely well in controlling coliform bacteria in the distribution system as well as dramatically lowering the levels of disinfection byproducts. US EPA recently required that concentrations of these byproducts, which are compounds known as Trihalomethanes and Haloacetic acids, be reduced. We are in full compliance with those new lower limits.

Each year the Washington Aqueduct laboratory conducts more than 65,000 individual tests on water samples. We are looking for bacterial, as well as organic and inorganic compounds and metals. We have state of the art equipment and are certified by US EPA for the tests we do. Hundreds of elements and compounds are addressed. The goal of this is to know what's in the drinking water and to make sure that the treatment operations are operating to properly protect the consumer.

Potential contaminants of interest such as arsenic and lead are routinely tested for.

Water Analysis Reports:

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001