First Defense®

First Defense is a versatile stormwater separator with the highest approved flow rates in the United States, enabling engineers and contractors to save site space and projects costs by using the smallest possible footprint.

It works with single and multiple inlet pipes and inlet grates, and is easily maintained from the surface by standard vacuum tanker.

First Defense HC_Screen_Hero

First Defense HC_Screen_Hero

First Defense HC_Screen_Hero


Designed with site flexibility in mind, the First Defense stormwater separator provides versatile capture of sediments, trash and floatables that allows engineers to maximize available site space without compromising stormwater treatment level.

First Defense is available in different configurations to comply with stormwater regulations defined by various jurisdictions. 

Targeted Pollutants

  • Coarse
  • Fine particles
  • Trash
  • Floatables


The First Defense reliably treats runoff from impermeable surfaces across a broad range of catchments.

First Defense also operates successfully as part of a management train alongside other proprietary or natural drainage features, for example as treatment before infiltration.

  • As part of LID or LEED and Sustainable Drainage Systems (SuDS)
  • Stormwater treatment at the point of entry into the drainage line
  • Sites constrained by space, topography or drainage profiles with limited slope and depth of cover
  • Retrofit installations where stormwater treatment is placed on or tied into an existing storm drain system
  • Pretreatment for filters, infiltration and storage


  • Cut footprint size, cut costs
  • Adapt to site limitations
  • Prevent washout
  • Save installation time


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