Drafting stormwater regulations that are clear, comprehensive and effective is crucial to protecting and preserving receiving waters.  The Clean Water Act has yielded a wide spectrum of local stormwater regulations and policies, but many leave something to be desired when it comes to actually mitigating the impacts of urban runoff.  It has been our experience that many local regulations are missing core components that are invaluable in achieving our ultimate goal.

Below are five key concepts that should be factored into local stormwater regulations in order to increase program effectiveness.

1. Avoid Vague Language - Regulations need to establish specific treatment requirements and policies governing how to size and utilize different types of BMPs.  Pollutants of concern and policies regarding their removal should be clearly identified.  Terms like maximum extent practical become nearly meaningless at the project level.  Additionally, clear guidance on proper siting, sizing and performance expectations for different BMPs is crucial.

2. Volume Reduction Won’t Fix Everything – Updating regulations to encourage the use of LID techniques and ultimately keeping more water on-site are to be applauded and encouraged.  However, stormwater policies must acknowledge that on many sites it will not be practical to address all of the stormwater runoff through volume reduction strategies alone.  This is particularly true in urban areas.  Flow through treatment practices must be included in the BMP toolbox.

3. Require BMP Maintenance - Regulations need to require maintenance for all BMPs. Maintenance requirements for stormwater treatment systems should also be designed to empower the regulating body to enforce maintenance requirements.

4. Moving Beyond 80% TSS – The days of assuming 80% TSS removal means all our problems are solved have passed us by.  Reducing solids loads is important, but there are often other pollutants of concern like phosphorus that are not adequately addressed by targeting only solids.  Additionally, we now know that TSS as an analytical measure often underestimates the solids load transported by urban runoff.  Today we need regulations that foster runoff volume reduction and identify treatment practices capable of addressing known pollutants of concern. 

5. Proprietary BMPs - Careful attention is needed when regulating proprietary BMPs. Many of these practices have been in use for more than a decade, but agencies often still fall short when it comes to regulating them.  Proprietary practices should be evaluated through a credible evaluation program before acceptance.  Additionally it is critical that local regulations establish approval procedures for these practices that link device specific acceptable sizing to published performance testing.  Since many of these practices are flow through systems, it is also crucial that a local water quality flow be identified along with the level of treatment that must be achieved when treating said water quality flow