Overview
Rain gardens
A rain garden intercepts runoff from a roof, driveway, or patio and holds it in a shallow basin long enough for it to infiltrate — typically within 24 to 48 hours, which is short enough that it never breeds mosquitoes.
The four decisions
- Catchment. Which surfaces drain into it, and how many square feet do they cover.
- Soil. How fast water moves through your ground, measured with a percolation test you can do with a shovel and a bucket.
- Size. Derived from the first two. This is where most projects go wrong.
- Plants. Species that tolerate both saturation and drought, chosen for your region.
The detailed guides, the plant selector, and the sizing calculator live on the rain garden section of this site: