Anticipating Washington State’s New Industrial Stormwater General Permit

The Washington Department of Ecology is in the process of renewing the current Industrial Stormwater General Permit (ISGP), which is set to expire on January 1, 2015.  Current permit holders will need to reapply for continued coverage by July 1, 2014.  The 2015 version of the ISGP will mean little or minor changes for some permittees, but will have significant changes for others. The good news is that for most permittees, not much is likely to change in the 2015 version:  the benchmark threshold concentrations (i.e., pollutant concentrations below which a water quality violation is unlikely) will remain the same, as will the types of facilities required to have coverage.

There are, however, some minor tweaks being contemplated for the ISGP’s monitoring and reporting requirements.  For example, Ecology may strengthen the language that prohibits the comingling of stormwater.  The current permit prohibits the comingling of stormwater with process waste water, but it does not expressly prohibit comingling with stormwater from other sites, such as industrial business parks with shared treatment facilities.  The new permit will likely require sampling before any comingling takes place with off-site sources.  Another monitoring change being considered is the timing for the first fall storm event.  The current permit requires permittees to sample stormwater discharge from the first fall storm event occurring after October 1 of each year.  That October 1 date is likely to change to September 1.  And finally, annual report deadlines are likely to move to February 14 from the current due date of May 15.

More significant changes are being proposed for transportation facilities and facilities discharging to major sediment cleanup sites, like the Duwamish.  For these facilities, the agency is considering new monitoring requirements and benchmarks.  Transportation facilities will likely see required monitoring for Total Petroleum Hydrocarbons (NWTPH-Dx) with a benchmark of 10 or 15 mg/L.  There may also be new best management practices or BMPs for marine terminals coming out of a study conducted by the Washington Public Ports Association.  If the study is completed in time, Ecology may include it with the draft permit during the upcoming public comment period, which is set to begin on April 16, 2014.  Finally, permittees at sediment cleanup sites will likely be required to monitor for Total Suspended Solids (TSS) with an expected effluent limit of 30 mg/L. Permittees at these sites also may be required to routinely clean out stormwater pipes under their control downstream of their sampling locations.

The draft permit and fact sheet are expected to be ready for public comment on April 16, with public meetings taking place throughout the month of May.  A more detailed schedule for the 2015 IGSP is available here:  http://www.ecy.wa.gov/programs/wq/stormwater/industrial/index.html.