West Des Moines Water Works
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PFAS in Finished Water


West Des Moines Water Works has been informed by the Iowa Department of Natural Resources that three of its shallow wells and finished water contain trace amounts of an emerging class of chemicals called per-and polyfluoroalkyl or PFAS. The sampling was conducted as part of a state-wide sampling effort being conducted by the IDNR this past fall. The threshold for health concerns for two of these compounds detected is 70 parts per trillion (ppt). The WDMWW results were a fraction of that level. The remaining compounds that were also detected in very low levels do not carry health advisories. Our drinking water is safe and in compliance with all standards set by the DNR and EPA. This category of chemicals is gaining awareness as water standards evolve. This is the first time any of the WDM Water Works' wells or finished water registered a detectable level of PFAS substances.


In 2014, WDMWW finished water was tested under the Unregulated Contaminant Monitoring Rule (UCMR) for 22 PFAS compounds with no detections found. The PFAS category contains a number of compounds, two of which now carry a health advisory—perfluorooactanic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). In WDMWW finished water produced at the A.C. Ward Municipal Water Treatment Plant, the presence of PFOA and PFOS were detected at 2.9 ppt and 2.4 ppt, respectively—well below the health advisory levels of 70 ppt.A part per trillion or ppt amounts to one drop of water in an Olympic swimming pool. In this case, the WDMWW detections of PFOA and PFOS is 2.9 drops and 2.4 drops of water in an Olympic sized pool, respectively. In compliance with IDNR’s testing protocol, the Water Works will increase testing and monitoring frequency. WDMWW will conduct research to determine whether the source or sources of PFAS compounds in the utility’s raw source water can be identified. Since no threat to safe drinking water currently exists, WDMWW will continue to monitor and determine appropriate strategies if levels substantially increase and near the health advisory limit.


The utility has and will continue to be in regular contact with IDNR regarding the detection of PFOA and PFOS and appropriate strategies to employ, if needed. The presence of PFOA and PFOS could be new, but it may also reflect the availability of more refined and accurate testing, which now can detect levels as low as 1.9 ppt compared with earlier methods that could only detect levels as low as 17 ppt. One particular shallow well reported higher numbers than the others, and we will minimize its use until we can address its issues. WDM Water Works will also work with our blending processes of shallow and deep wells to achieve the lowest levels possible of these substances in the water we produce.


PFAS substances emanate from manmade chemicals used in a variety of manufacturing applications and products including carpet, waterproofed clothing, cookware coatings such as Teflon, fire-fighting foam and food packaging just to name a few. Moreover, these substances are persistent, meaning they do not degrade or break down naturally in the environment.


The full test results will be posted by the IDNR at the agency’s PFAS webpage (https://www.iowadnr.gov/Environmental-Protection/PFA).


More information about PFAS and the IDNR action plan is also available on the agency’s website. West Des Moines Water Works will continue to test, monitor and inform its customers of detectable PFAS levels.


Additional Resources:


Press Release and Analytical Report 


Q&A for PFAS


EPA PFOS and PFOA Fact Sheet


IaDNR PFAS Action Plan