The United States Environmental Protection Agency (EPA) recently celebrated the 40th anniversary of the Safe Drinking Water Act (SDWA), which Congress passed on December 16, 1974, directing EPA to implement a series of regulations and standards to protect public drinking water from source to tap. The law was amended in 1986 and again in 1996 to include additional actions to protect drinking water, including those that recognize the needs for source water protection, training for water system operators, funding for water system improvements, and public information about the quality of treated water to inform water consumers and hold water delivery systems accountable.
Continued high nitrate levels in Des Moines Water Works’ source waters – the Des Moines and Raccoon Rivers – forced Des Moines Water Works to activate its nitrate removal facility early December 2014. On December 16, 2014, the 40th anniversary of the SDWA, the denitrification facility remained in use in order to ensure Des Moines Water Works’ finished drinking water was safe for consumption, as defined by the SDWA.
In addition, Des Moines Water Works was forced to use emergency water storage from Maffitt Reservoir at the L.D. McMullen Water Treatment Plant. Water at Maffitt Reservoir is considered emergency storage water for use during exceptional instances of water quantity and water quality. Use of the emergency water today, reduces the amount of storage water available for use during high customer demand periods.
“Des Moines Water Works staff has exercised extensive efforts to reduce nitrate levels to an acceptable level, as prescribed by the United States Environmental Protection Agency,” said Bill Stowe, CEO and General Manager, Des Moines Water Works. “Because nitrate continues to be introduced in the watershed at high levels, we are forced to use emergency storage water, in addition to running the nitrate removal facility, in order to maintain delivery of safe drinking water to our customers.”
The EPA’s maximum contaminant level (MCL) for nitrate in finished drinking water is 10 mg/L. The levels seen in the Raccoon and Des Moines Rivers last fall and this winter are unprecedented for this time of the year. The monthly averages are as follows:
Raccoon River Des Moines River
September 2014 11.89 mg/L 7.20 mg/L
October 2014 13.23 mg/L 11.15 mg/L
November 2014 13.43 mg/L 11.96 mg/L
December 2014 12.56 mg/L 11.14 mg/L
Des Moines Water Works remains committed to fighting for cleaner source water on behalf of the 500,000 central Iowans Des Moines Water Works is pleased to serve.
According to the Iowa Nutrient Reduction Strategy, approximately 92% of nitrate loads enter our water resources through agricultural sources that are not currently being subject to any mandatory regulations, despite longstanding legal mandates to address such pollution.
“While Des Moines Water Works continues to incur costs and reduce available water storage, polluters of the watershed are not regulated,” said Stowe. “This is a public health issue for our customers. We cannot continue to meet the increasing water demand of our customers without regulation of pollutants in our source water.”
In order to ensure that tap water is safe to drink, the EPA prescribes regulations limiting the amount of nitrate levels in water provided by public water systems. The greatest health risk posed by high nitrate concentrations is for infants under six months of age. Nitrate can transform into nitrite in the infant’s body, reducing the ability of the baby’s blood to carry oxygen. This may result in Blue Baby Syndrome. Des Moines Water Works’ finished drinking water nitrate concentration is currently below the level which is indicated to cause these health implications. If you are caring for an infant, you may wish to seek advice from your healthcare provider.
Despite the high levels of nitrate in the source waters, Des Moines Water Works’ finished drinking water remains safe for consumption.