On-site water remediation is a catch-all term that describes several techniques used to deal with stormwater, greywater, and blackwater. Most of these techniques involve natural filtration systems that allow water to be re-used within the building, elsewhere on site, or safely returned to the Earth.

Issues Addressed

A vast number of issues are addressed through on-site water remediation:
  • World-wide potable water scarcity (greywater reclamation)
  • Combined sewer overflow events (permeable paving, rainwater harvesting)
  • Flooding (permeable paving, rainwater harvesting)
  • Ground water recharge (permeable paving)
  • Drainage (permeable paving)
  • Irrigation (greywater reclamation, rainwater harvesting)
  • Water Treatment (constructed wetlands)

Greywater Reclamation. Source:

Permeable paving. Source: WERF

Rainwater harvesting. Source: RIBA

Constructed wetlands. Source: The Willow School


Not all of these solutions are applicable for every project. Many depend on the characteristics of the site.

Greywater Reclamation

Requires space for a cistern. This can be buried underground, exposed at grade, or inside the building.

Permeable Paving

Nearly every site has paving to some degree, and every paved surface can be permeable. Differing types of pavers are available depending on the soil conditions and load to be supported.

Rainwater Harvesting

Same as greywater reclamation, above.

Constructed Wetlands

In the most advanced applications, needs a fair amount of land, but smaller installations have been successful.



Greywater reclamation is probably the most realistic for an office building due to limitations of available land needed for the other techniques. Large numbers of bathrooms (and the resulting greywater) naturally make reclamation an easy decision.

Recreation Facilities

These buildings are in parks most of the time and therefore should usually have the land available for all types of water remediation. Putting them in this type of public facility is also way to educate the public.

Sanitation Facilities

Similar to recreation facilities, space is not usually a constraint, plus the educational component is even more important when the Department of Sanitation sets the example.