Rain Gardens

Install a rain garden on your property to prevent stormwater from reaching the nearest storm drain or waterway.

What is a Rain Garden?

A rain garden is a landscaped, shallow depression in your lawn designed to collect stormwater from your roof, driveway, or other impervious surface before it reaches the nearest storm drain or waterbody.

By trapping stormwater and allowing it to seep naturally into the ground, rain gardens minimize runoff, remove pollutants, reduce flooding, and help recharge groundwater supplies.

In addition to their value in preventing stormwater pollution, rain gardens are typically planted with native shrubs or perennials, adding beauty to your lawn and providing habitat for birds, butterflies, and beneficial insects.

Rain Gardens Are Not Bioretention

You may be familiar with the term bioretention as a stormwater management technique. Although rain gardens and bioretention basins function similarly, they are very different! Bioretention basins require detailed engineering, and are usually much larger with sophisticated conveyance devices (e.g., underdrains, overflow structures, etc.) and a prescribed soil mix to promote filtration by stormwater. Bioretention is often used when managing stormwater at new development projects or retrofits. Rain gardens are small in scale—ideal to manage runoff from smaller drainage areas such as residential rooftops and driveways—and utilize native, or modestly amended soils. Proper rain garden design may be achieved through appropriate site selection and simple sizing techniques.

Installing a Rain Garden

Am I Required To Have A Rain Garden On My Property?

Rhode Island Stormwater Solutions is encouraging property owners to install rain gardens as a voluntary practice to help reduce stormwater pollution. However, new development or redevelopment projects may require a rain garden or some other type of Low Impact Development (LID) technique to manage stormwater. Rhode Island stormwater regulations enacted in 2011 require individual single-family residential development or redevelopment projects to treat the water quality volume, or one inch of stormwater runoff, from any new rooftop, impervious surfaces of 600 square feet or greater in size, and all new driveways and parking areas.

Rhode Island Stormwater Management Guidance for Individual Single-Family Residential Lot Development is a guidance document produced by The Rhode Island Department of Environmental Management (RIDEM) and the Rhode Island Coastal Resources Management Council (RI CRMC) to assist with designing, installing and maintaining stormwater management practices that meet the requirements for new or enlarged single-family dwellings, driveways and parking areas, including rain gardens.

RIDEM Office of Water Resources has more information about managing stormwater at new development projects.

Getting Started

With proper guidance, rain gardens are not difficult to install and are easy to maintain. Rain gardens typically require digging a shallow depression, usually 6 inches deep, berming the edges to help keep water in and allow for proper infiltration, amending the soil, and planting with native perennials.

Finding Resources

See our resources section for a series of links to helpful websites, factsheets, and presentations and even a mobile app to help you design your garden. There are numerous design guides available with detailed instructions for installing a rain garden – including site assessment, sizing, design, installation, and plant selection guidance.

Maintaining a Rain Garden

How Do I Maintain My Rain Garden?

A properly designed rain garden should not be much different than maintaining any other garden on your property—weekly watering and weeding when the garden is first planted, followed by annual mulching, pruning, and replacing any dead or diseased plants. Rain gardens also should be inspected regularly for potential erosion problems and sediment accumulation. For more detailed maintenance information, see our factsheets below.