DES MOINES, Iowa — Nitrate milligrams per liter has become a phrase central Iowans are all too familiar with this year as Central Iowa Water Works has had a mandatory restriction in place for lawn watering for the last several weeks.

The nitrate removal facility that sits in Des Moines is capable of processing 10 million gallons of water per day, and prior to the water restrictions, there were days where demand would reach 70-80 million gallons per day. That is when Central Iowa Water Works decided to have voluntary restrictions, then mandatory.

“We’ve seen our demand reduce greatly to make it that we are completely able to meet that 10 milligrams per liter standard and keep everyone safe and healthy,” said Lisa Morarend, a chemist with Central Iowa Water Works.

CIWW uses a $100,000 instrument to test the nitrate levels to an accuracy of 1/100 of a milligram per liter. These samples are taken and tested every day to confirm the amount of water that must be cleaned through the removal facility every day to keep up with demand. The testing is so frequent that there is a sample run through the instrument every 18 minutes, which then allows the results to be shared with the public and water usage decisions can be made.

“There’s a big difference for us between five milligrams per liter of nitrate and ten, that would be a huge difference for us,” said Morarend while explaining her confidence in the water being safe, mentioning herself and her family drinks the treated water.

Morarend said the high levels of nitrates this year, as always, have a lot of variables. Drought conditions in previous years did not allow the nitrogen to be washed out of fields. But with extra rainfall this year, Morarend said the nitrate from previous years has been running off into the river, causing the issue.

“Thankfully the lawn watering ban has been incredibly effective and so we have not exceeded the drinking water standard of ten milligrams per liter,” said Tami Madsen, the Executive Director of Central Iowa Water Works. “So we do not anticipate needing to put any kind of further restriction or a ban whatsoever.”

The CIWW lawn watering ban went into effect 12 days ago, with the Des Moines Water Works nitrate removal facility needed after running for 55 days straight.

A couple Saturdays ago, the City of Clive handed out 343 violation notices for individuals with automated irrigation meters, informing the customer of the need to comply. As of June 19, Des Moines had only sent out 30 warnings, Ankeny had 23, Johnston 63, Norwalk 22, Waukee 56, and Polk City 65.

Warren Water District told WHO 13 News that there were no warnings or citations issued as there was compliance within 48 hours. Grimes is not enforcing the lawn watering ban as the water there comes from local wells. West Des Moines Water Works sent emails to customers with 1,316 irrigation meters pumping 100 gallons an hour or more, prior to the ban. The number of meters has now dropped to 145. Urbandale told WHO 13 News that 180 door hangers were put out when the ban started to residential and commercial properties, and now all are in compliance.

CIWW did not have an estimate to when the lawn watering ban would be lifted, but remained hopeful that the nitrate levels would drop. Both the Raccoon and Des Moines rivers sit near 14 milligrams per liter before treatment. That is easier for the removal facility to process and keep up with demand, compared to early June when the Raccoon was at 20 milligrams per liter.

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