Des Moines asked to rethink lawn watering now to minimize nitrate crisis

• It becomes harder to temper demand once the schedules are in place, Central Iowa Water Works executive director Tami Madsen tells Axios.

Driving the news: Nitrate levels of the untreated water collected from the Des Moines and Raccoon rivers, the two main sources of the metro's water, have for weeks hovered at or above a federal nitrate maximum level of 10 mg/L.

• It's unusual for nitrate removal facilities to run in the winter, but this year's started on Jan. 6 to ensure safe drinking water.

State of play: Nitrates are tasteless, naturally occurring compounds that can become harmful to human health when levels in drinking water are too high.

• Fertilizer and animal waste runoff have contributed to the problem, and the metro has been dealing with high levels for decades.
• Periods of warm weather in recent months likely contributed to higher nitrate levels.

Stunning stat: Nitrate removal can cost the metro up to $16,000 a day.

The latest: High nitrate levels reached early in the year have foreshadowed continued high levels throughout the year, John Lawrence, an emeritus professor at Iowa State University, tells KCCI.

Reality check: It's too early to predict whether central Iowa will face lawn-watering restrictions this summer because rainfall and river conditions can change quickly, and forecasts aren't guaranteed.

Yes, but: Lawn irrigation is the main contributor to summer usage spikes, and employing conservation practices is a reasonable step, Madsen said.

• CIWW wants to stay within its nitrate removal capacity range for multiple reasons, including financial ones, since water utility budgets are tied to usage, Madsen said.

The intrigue: Lawn watering is often unnecessary and may even harm the grass, according to ISU turf specialists.

What's next: CIWW plans to promote lawn-watering efficiency in the coming weeks, including sharing guidance from Iowa scientists.