How to Build a Rain Garden

In this section:

a residential rain garden

A rain garden is an easy, low cost way to infiltrate your stormwater and bring some more beauty into your landscape.

1 – Pick a Location

Find a spot in your yard where you can easily direct the runoff from your downspout or other impervious surface. Do a “perc test” to ensure that the soils in that spot can soak up rain water. To avoid drainage problems, place your rain garden at least six feet from your house if you have a basement (two feet if you don’t) and five feet from your property line. Call your local jurisdiction to find out if you need a permit to disconnect your downspout or if there are special requirements.

How to Do a Percolation Test

performing a percolation test

  1. Dig a hole at least twelve inches deep.
  2. Fill it with water and let it drain.
  3. Fill it with water a second time. If the water drains at least half an inch in an hour the second time you fill it, your soil has adequate drainage for a rain garden.
2 – Dig the Basin

Dig a shallow depression to create a rain garden area about six inches deep. You can make it as long and wide as you like – the bigger it is, the more rain water it can soak up.

Call before you dig logoDon’t forget to call before you dig so you don’t hit any buried utility lines! In Oregon call 1-800-332-2344, or 811.
3 – Create a Berm

Use the soil you dig up to create a berm (and pack the soil well!) on the down slope side and direct the overflow safely away from nearby buildings. Make the bottom of your rain garden level. If you like, you can amend the soil in your rain garden with compost.

4 – Get Planting!

Plant your plants and then mulch. Water the plants until they are established. Here are two sample designs, each based on the amount of sun the area receives:

  1. Shady Rain Garden
  2. Sunny Rain Garden
  3. Stay tuned for more designs in the sample designs page.

5 – Help Others Learn About Rain Gardens

Help us track of the number of rain gardens out there and receive a free rain garden sign by registering your rain garden.