Proprietary stormwater BMPs are manufactured systems that use proprietary settling, filtration, absorption/adsorption, vortex principles, vegetation, and other processes to remove pollutants from stormwater runoff. Proprietary BMPs are commonly used as pretreatment for other BMPs, as described in this section (Proprietary Pretreatment Device), or as treatment systems in retrofit applications where physical site constraints limit the use of other retention and/or treatment BMPs (refer to Chapter 11 - Proprietary Stormwater BMPs for use of Proprietary BMPs for stand-alone treatment).

Common types of proprietary BMPs include hydrodynamic separators, media filtration devices, and catch basin inserts. This category of stormwater BMPs also includes new and emerging technologies that are continually coming onto the market.

Chapter 11 - Proprietary Stormwater BMPs of this Manual further describes the appropriate uses and limitations of proprietary stormwater BMPs, third-party BMP performance verification requirements for proprietary BMPs, and general design criteria and maintenance requirements.