Is Storm Water A Pollutant?

Is Storm Water A Pollutant? Federal Court in Northern Virginia Says No to EPA Regulatory Effort

By:  John R. Embick, Esq. -- January, 2013

Co-Chair, Environmental Law Section

In a recent decision handed down on January 3, 2013, Judge Liam O’Grady ruled, on a motion on the pleadings, that EPA did not have authority under the Federal Clean Water Act (“CWA”) to set a Total Maximum Daily Load (“TMDL”) for storm water flow rates affecting an impaired stream (the Accotink Creek) in Northern Virginia.  The case is Virginia DOT, et al., v. U.S. EPA, C.A. No. 1:12-CV-775 (USDC ED Va).

The CWA gives states and the federal government the right to impose a “pollution diet” on waters that are chronically impaired and do not meet the CWA standards (i.e., that  waters generally be fishable, swimmable, etc.) set for those waters.  Because the Accotink is on the impaired waters list, Virginia or EPA must develop TMDL limits to achieve the CWA standards. TMDL limits represent extra or additional effluent discharge controls designed to reduce the amount of pollutants and improve water quality.

EPA determined that a problem affecting the Accotink was excess sediment flowing into the creek.  Too much sediment has deleterious effects on a stream ecology and water quality.   In the VaDOT case, EPA chose to control sediment loading by means of regulating storm water flows.  The decision did not discuss the type of storm water flow controls, but we assume that this means that Virginia had to come up with ways of reducing the amount of storm water that discharged into the Accotink, and this usually means the implementation of infiltration systems.  These controls usually are expensive to implement.

Curiously, EPA chose to regulate storm water flows in this case, as opposed to setting a limit for sediment concentration in discharges.   In most prior TMDL permits, EPA chose to impose sediment limits. EPA apparently has only attempted to set storm water flow rates (for sediment control) in only four other TMDL permits.  Of the four permits, all the storm water flow rates limits were challenged, and one case settled.  The other three cases are still pending.

In the VaDOT case, both sides agreed that sediment is a pollutant, and storm water is not a pollutant (under the definition provided in the CWA).  EPA argued that it was permitted to use storm water flows as a “surrogate” for sediment control. 

Using the Chevron analysis standard for resolving questions of statutory interpretation, the court found that that the CWA did not permit EPA to regulate a non-pollutant. The case was remanded to EPA.

This is an interesting dispute about a regulatory technicality.  Most water scientists readily agree that sediment is a pollutant and that storm water flow causes erosion and sedimentation, as well as other pollution.  It stands to reason that reducing storm water flows will reduce sediment pollution.  This issue is whether EPA has the regulatory authority to do so.

We really do not know why EPA is “testing” a storm water flow TMDL, although we suspect that this is related to EPA continuing efforts to exert more control over storm water runoff from non-point sources (a major source of water pollution).  EPA is working on a new federal storm water rule (due in 2014), and some observers believe that EPA is considering using storm water flow controls in amendments to the Post Construction Storm Water permit program (the permits which must be obtained to control runoff from new construct sites after construction is completed).