Local officials are warning more than half a million Iowans in the state's capital city and suburbs that near-record level of pollutants in its rivers could make drinking water dangerous if immediate steps are not taken to reduce demand.

Des Moines spraygrounds normally operate from 9 a.m. to 8 p.m. daily during the summer, but are now operating from noon to 6 p.m.

There is not a shortage from water sources in the area, but treatment facilities are struggling to keep up with high levels of nitrate in the rivers that supply the system.