NITRATE IN DRINKING WATER
What our customers want to know.

When the Columbus Division of Power and Water notifies the public about elevated nitrate levels in drinking water many customers call us with questions:

What causes elevated nitrate in drinking water?
Nitrogen occurs naturally and is essential for plant growth. That is why it is applied as fertilizer to farmland, lawns, and golf courses. During certain weather conditions, especially after heavy rains, nitrate can run off into streams and rivers where it reacts with water to form nitrate.

The Scioto River receives runoff from more than 1,000 square miles of land before reaching the Dublin Road Water Plant intake.  Therefore, it is more susceptible to nitrogen runoff than the other water sources in Columbus.

How were acceptable nitrate levels established by EPA?
The acceptable level for nitrate in drinking water was established by the Environmental Protection Agency (EPA) as a safeguard to protect infants. Because of their immature digestive system, infants under six months of age convert nitrate to nitrite which interferes with the oxygen carrying capability the blood.  Therefore, the EPA established the “maximum contaminant level” for nitrate in drinking water at 10 milligrams per liter or 10 parts per million.

Who is affected . . .  who is not?
Levels of nitrate in Columbus drinking water pose no threat to the majority of people. Only infants less than six months of age are affected when the level of nitrate is above the standard. Pregnant or nursing women need not be concerned about the levels of nitrate in Columbus water. Very little of the nitrate/nitrite consumed by the mother will be passed on to the developing fetus or nursing infant. Many vegetables and processed meats contain nitrates. Water is generally a minor source of nitrate in the diet.

Why and how is the public notified?
Water suppliers are required to notify the public when nitrate levels are more than 10 parts per million in the drinking water. Occasionally, the water from the Dublin Road Water Plant exceeds this standard.  The Columbus Division of Water’s Water Quality Assurance Laboratory routinely tests surface water samples and determines when nitrate levels are rising.  A “Nitrate Advisory” is sent to newspapers and TV and radio stations when the nitrate level exceeds 10 parts per million.  Through the media, parents of infants are notified of the specific area impacted and are advised to buy distilled water for the baby’s needs until the advisory is lifted.  

The Dublin Road Water Treatment Plant supplies water to (see Distribution Map):