In a decision likely to impact many publicly-owned treatment works (POTWs) around the country, on March 25, 2013, the U.S. Court of Appeals for the Eighth Circuit struck down EPA's prohibitions against the practice of blending wastewater at POTWs during wet weather events, and against the use of mixing zones in permits for compliance with bacteriological standards in recreational waters.  The decision, captioned as Iowa League of Cities v. EPA, Appeal No. 11-3412, can be accessed here. 

The appeal stems from EPA's issuance in 2005 of a draft "blending policy," stating that bypassing part of the treatment process during heavy rains to avoid property damage or loss of biological treatment, and then blending the flow back in at a later point in the process, is an illegal, unpermitted bypass unless the operator (i) demonstrated that it was not feasible to eliminate the bypass and (ii) implemented all feasible capital and O&M steps to minimize the practice.  Because most, if not all, of these wet weather bypasses were constructed under permits issued by state agencies and the cost to eliminate them would be millions of dollars, thousands of local governments and their trade groups filed comments objecting to the draft policy.  Other objections included that the recombined flow is monitored under the discharge permit, thus ensuring protection of water quality, and that EPA could not dictate internal treatment plant design and operation, but instead its jurisdiction was limited to the "end of the pipe."

Undaunted by the criticism, EPA did not withdraw the policy, but also never finalized it.  Instead EPA instructed its regional staffs to enforce the policy indirectly by informing states with delegated permit programs that failing to enforce it would lead to EPA objecting to permit renewals for POTWs and to potential federal enforcement. 

The second part of the appeal dealt with EPA's issuance of a series of memoranda to state agencies prohibiting the use of mixing zones for complying with bacteria standards in recreational waters.  Local governments and their trade groups objected because EPA's existing rules left it to the discretion of the states to allow such zones as part of their water quality standards programs. 

The Iowa League of Cities argued that these two prohibitions constituted de facto amendments to EPA's existing rules without proper notice and comment, and the Court of Appeals agreed, declaring them null and void.  The Court also ruled that the blending policy illegally sought to give EPA control over the internal design and operation of POTWs, when its jurisdiction is limited to the discharge to the receiving stream.  EPA has not indicated whether it will appeal the adverse ruling.