Rain Gardens

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What is a rain garden?

Rain gardens are shallow, planted depressions that absorb water from your roof, allowing it to drain directly into the soil.

Typically, a downspout from your home is disconnected from the sewer system and diverted into the rain garden, which can prevent hundreds of gallons of rainwater from entering Ambler storm drains. Rain gardens are one of the most cost effective ways to manage stormwater runoff and can be a beautiful addition to your existing landscape design.

  • Participant cost: Clean Streams, Clean Water will contribute about $13 per square foot for a rain garden up to a maximum of $1280. On average, a rain garden is $17-$20 per square foot.

  • A rain garden should have an area about 20% the size of the roof, patio, or pavement area draining into it. A typical rain garden for a residential home or small building is between 100 and 400 square feet. Regardless of the size, big or small, each rain garden can make an impact.

  • Rain gardens are shaped longer than they are wide and positioned perpendicular to the slope of the land in order to catch the maximum amount of rainfall. Rain gardens should be placed at least 10 feet away from building foundations and should not be located where water ponds for an extended period of time.

About our rain gardens:

Preliminary testing: The contractor will perform an infiltration test, which determines how much water your soil can hold. In general, soils in Ambler have a lot of clay. 

Design: Our expert contractors will work with you to create a design that is appealing and unique to your property.

Siting the rain garden: Rain gardens must be planted in an area that is at least 10 feet from a below-ground basements and crawlspaces.

Dimensions and Materials: Rain gardens are excavated to a depth of 6” to 12”. Then, the garden is filled with a stormwater-friendly mix of soil, sand, and compost.


  • Our rain gardens are typically planted with native, drought-tolerant perennial species. These species do the best job of absorbing and filtering stormwater and are very low maintenance.

  • Our rain gardens are planted with young specimens that will thrive over time. The rain gardens are designed to fill in completely over 1-3 growing seasons. In time, they create wonderful habitats for butterflies and birds.


Rain garden maintenance:

Water: Water the rain garden regularly (once per week for the first 2-3 months or so). Deep watering once per week is preferable to daily, shallow watering. Once the plants’ root systems are established, it will only need watering during heat waves or long periods without rain.

Weed: Weed and prune as you would any garden.

Do not plant edible food in a rain garden: Stormwater running into the garden may carry dirt and debris not suitable for edible plants. In addition, all urban soils should be tested for lead and other potential contaminants before being used for growing edibles. 


  • After heavy thunderstorms or downpours, check for signs of erosion or gullies. Add more plants, river rocks or mulch to address these concerns.

  • Do not be afraid to move plants around if you think they would do better in drier or wetter parts of the garden.

  • View this list for information about the types of plants that are suitable for a rain garden.

Sign Up

Please sign up for a workshop (attendance is required before installation). 

Sign up for a workshop and request a storm water feature