Subsurface Infiltration Beds

Subsurface Infiltration Beds are large reservoirs located underground that are designed to capture, temporarily store, and infiltrate stormwater over several days in the surrounding soil from an area up to 10 acres. While they are typically made up of a rock storage bed underground, other common systems include pre-manufactured pipes, vaults, and modular structures. These systems were developed as alternatives to basins and trenches for sites that have limited space and can be located under paved areas or grassy open spaces.

While these systems free up space by managing stormwater underground, their installation and maintenance costs are higher.  Regular inspection and maintenance are critical to support function and avoid system failure.

Subsurface Infiltration beds, dry wells, infiltration trenches, and infiltration basins provide similar stormwater management capabilities. Determining the right BMP to use will depend on your site needs, landscape limitations, space, and budget.

Subsurface Infiltration Bed Factsheet - SEMCOG


Maintenance is critical for subsurface infiltration beds to function over the years. Having a maintenance plan in place will help ensure completion of tasks and that an appropriate timeline is followed.