Des Moines Water Works uses both the Raccoon and Des Moines Rivers as water sources. By using surface water, seasonal variations can occur. The recent warm-up in temperatures has caused increased runoff into our water supply, requiring Des Moines Water Works to use more chlorine to achieve the desired chlorine levels in the finished product.
Both rivers are currently experiencing elevated levels of ammonia. Disinfection with chlorine is more difficult when ammonia is present in source waters. Ammonia consumes chlorine, leaving it unavailable for disinfection. This requires addition of extra chlorine to eliminate the ammonia and maintain adequate disinfection. For these reasons, chlorine levels have been purposefully higher for the past three weeks. Chlorine levels in the water leaving Des Moines Water Works’ treatment plants are monitored continuously to ensure they do not exceed the maximum allowable limit set by Environmental Protection Agency (EPA).
Finished drinking water from Des Moines Water Works is safe to consume. Some people are more sensitive to these subtle changes in taste or odors. These conditions will improve as the weather stabilizes and levels of runoff decrease.