The Iowa Department of Natural Resources (IDNR) administers the Public Drinking Water Program in Iowa under delegation of authority from the United States Environmental Protection Agency (EPA). The 1996 re-authorized Safe Drinking Water Act (SDWA) requires that each state prepare an annual report on violations of national primary drinking water regulations within the state.
A public water supply (PWS) is defined as a system that provides water to the public for human consumption. In Iowa, there are 129 surface water systems, 28 groundwater systems that are under the influence of surface water, and 1,809 groundwater systems. 45% of the population is served by surface water or groundwater under the influence of surface water systems and 55% are served by groundwater sources. The mission of Iowa DNR’s Public Drinking Water Program is to protect and enhance the public health, safety, and quality of life for all persons by ensuring the public drinking water is safe to drink. The overall drinking water program compliance figures in 2010 continue to be very similar to those in the previous two years.
Compliance with Health-Based Standards
- No waterborne diseases or deaths were reported from Iowa public water supply systems (PWS) in 2010.
- Over 2.62 million people (of the 2.84M people served by PWS) regularly received water from systems meeting all health-based drinking water standards.
- Health-based drinking water standards were met by 91.0% of the 1,966 regulated public water supplies. There were 176 public water supplies that had 351 violations of a health-based drinking water standard: maximum contaminant level (MCL), maximum residual disinfectant level (MRDL), treatment technique (TT), or action level (AL).
- Eighteen of the more than 80 regulated contaminants were found at levels that exceeded the health-based standards during 2010. The top four contaminants based on total health-based standard violations, along with the percentage each contributed to the total number of health-based standard violations are; Total Coliform Bacteria (58.4%), Nitrate Nitrogen (8.3%), Fecal Coliform Bacteria (7.4%), and Nitrite Nitrogen (6.8%). Six other health-based standards were each exceeded at least once during the year: the maximum contaminant levels for chlorite and uranium; and treatment techniques for nitrate, contact time, gross alpha, and significant deficiencies not promptly corrected.
The complete 2010 report can be found on the IDNR website at, http://www.iowadnr.gov/Portals/idnr/uploads/water/wse/2010SAR.pdf