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To assist with its advocacy efforts on peak wet weather flow management, NACWA is conducting a survey of publicly owned treatment works (POTWs) about blending. NACWA has been advocating for years for a consistent national policy on blending, which can be an effective method for managing peak wet weather flows and protecting water quality. However, blending is still being targeted on both the regulatory and legislative fronts. Despite the 8th Circuit Court of Appeals 2013 ruling in Iowa League of Cities v. EPA, EPA continues to consider blending a bypass for POTWs outside of the 8th Circuit. In addition, Section 428 of the current Senate FY16 appropriations package would prohibit blending and sewer overflows for any POTWs that directly or indirectly discharge into the Great Lakes.

NACWA’s survey on blending will provide the Association with technical, legal, and policy information about the current status of blending at utilities across the U.S. NACWA is asking all POTWs that use blending – whether NACWA members or not – to complete this survey by Friday, September 4. Questions about the survey should be sent to This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

POTWs that discharge to the Great Lakes will be receiving a supplemental survey with questions directly related to Section 428 of the Senate appropriations package. These POTWs are asked to complete both the NACWA blending survey and the supplemental survey. Questions about the supplemental survey should be sent to This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Background Information

EPA proposed policies on blending in 2003 and 2005 in an attempt to provide national consistency, but did not finalize either proposal. Although EPA held a workshop on sanitary sewer overflow (SSO) issues and blending in 2011 and a public health forum on blending in 2014, the Agency has stated that it has no immediate plans to propose another blending policy. EPA has indicated that it will be developing a compendium of information to provide an overview of treatment options for wet weather flows and to highlight performance data from facilities that use blending, including facilities that use parallel treatment and those that do not.

In 2013, the 8th Circuit Court of Appeals stated in its Iowa League of Cities v. EPA decision that EPA was improperly regulating blending at POTWs and that the Clean Water Act’s secondary treatment effluent limitations apply only at the final point of discharge, not within a POTW’s internal treatment processes. However, since EPA has decided to apply this ruling only to POTWs in the 8th Circuit, blending is still viewed by EPA and many states as an illegal bypass at POTWs outside of the 8th Circuit. A petition for review has been filed in the U.S. Court of Appeals for the District of Columbia to contest EPA’s decision to limit the applicability of the Iowa League of Cities v. EPA decision, but that case has not yet been resolved.

NACWA is administering this survey for research purposes to enhance the Association’s advocacy efforts with the Obama Administration and Congress. In particular, the survey will help NACWA develop a better understanding of the costs and environmental benefits associated with treating peak wet weather flows with blending versus alternative methods of treatment. The survey will help to better inform NACWA’s advocacy on this important issue and allow NACWA to continue advocating for a sensible policy to allow POTWs to decide on the best treatment options for their peak wet weather flows.

In addition, NACWA is actively opposing current efforts in Congress to prohibit blending for some Great Lakes area POTWs. Section 428 of the Senate’s FY16 appropriations package for EPA would prohibit blending for all direct and indirect dischargers to the Great Lakes and require communities that operate combined sewer systems to eliminate all overflows by 2035. Prohibiting blending for these utilities would establish a precedent that could lead to additional prohibitions in other areas or on a national scale. The information collected in this blending survey, as well as the supplemental survey that will be sent directly to Great Lakes dischargers, will provide NACWA with important data to use in opposing this legislation.

Instructions for Survey

The online survey must be completed separately for each treatment plant operated by a clean water agency. Partially completed surveys cannot be saved. The entire survey may be viewed as a PDF document before entering the requested information. The survey respondent will be guided to different sets of questions depending on whether the facility serves a separate sewer system, a combined sewer system, or both. NACWA asks respondents to complete as much of the survey as possible. Questions may simply be skipped if the information requested is not available or if the utility prefers not to provide it. Educated guesses for those questions where information is not readily available would be helpful.

The information generated from this survey is confidential research information being collected by NACWA. The utility name and contact information will be kept confidential and will only be used by NACWA for quality control purposes. This information will not be reported to EPA or any other entity. Other information submitted for the survey will only be used in anonymous, aggregate form.

Please complete and submit surveys by Friday, September 4. Please contact Cynthia Finley at This e-mail address is being protected from spambots. You need JavaScript enabled to view it with any questions about the survey.