How to Make a Rain Garden: Size, Design & Plants

A rain garden catches some of that water where it falls.

What is a rain garden?

A rain garden is a shallow depression, typically a few inches to about 8 inches deep, planted with deep-rooted plants that tolerate both wet and dry conditions.

Why build a rain garden?

Soil and plant roots filter sediment, nutrients and other pollutants before water reaches streams.

Step 1: Choose the location

Downhill from a downspout, where you can direct roof water to it with a pipe or a shallow grassy or rocky channel called a swale.

Step 2: Test how well the soil drains

A rain garden only works if water can soak in.

Step 3: Work out the size

The size of a rain garden depends on how much area drains into it, your soil type and how deep you make it.

Step 4: Choose the depth and shape

Depth: most residential rain gardens are 4 to 8 inches deep.