Rain Garden FAQs

What is a rain garden?

Rain gardens are man-made landscape features that include a shallow (6 – 9 inches deep) depression designed to capture and reduce stormwater runoff. By installing a rain garden homeowners can intercept stormwater and keep it on their property. This allows stormwater to infiltrate into the soil rather than moving to a nearby ditch or stream. Rain gardens are particularly important in urban areas because developed land (pavement, buildings, and compacted soils) increases stormwater runoff. Rain gardens are one of several stormwater management practices that a homeowner can do to reduce their property's negative impact on water quality and flooding.

Why rain gardens?

Stormwater runoff carries pollutants like fertilizers, oil, animal waste, and dirt to local streams, lakes, and ponds and may contribute to flooding during heavy rainfall events. This puts added stress on these receiving bodies of water and their ecosystems. Excess discharge can impact streams by causing erosion, destroying habitat, and deforming natural channel flow. Ways to minimize stormwater volume leaving your property include utilizing storage devices such as cisterns or rain barrels. Contaminants discharged to streams can cause illness, impair ecological health, and increase water treatment costs. Simple practices around your home and in your neighborhood that can improve water quality include picking up pet waste, minimizing fertilizer use, and sweeping grass clippings from sidewalks and driveways.

Benefits of a Rain Garden

• Improves water quality.
• Alleviate problems associated with flooding and drainage.
• Enhance the beauty of individual yards and communities.
• Provide habitat and food for wildlife including birds, bees, and butterflies.
• Increases infiltration which recharges the groundwater supply.
• Protect against the negative effects of impervious surfaces created by development.

Will a rain garden integrate into the overall landscape design?

Rain gardens are temporary catchments so they may be periodically wet or dry. You will want to keep this in mind as you consider a location. They also need to be in a landscape position so that water will flow easily into the rain garden and, in the case of larger storms (rainfall is greater than 1 inch), overflow into the lawn or other area without causing damage or erosion.

Will rain garden plants fit into the landscaping scheme?

Locations with full sun will be best, but with proper plant selection partial sun locations can work as well. Rain garden plants need to be able to tolerate alternating wet and dry conditions. While there are a variety of plants suitable for rain gardens, you should consider how these plants will coordinate with the existing landscape.

How much will it cost?

The cost will be a function of the size, complexity of the draining and overflow system, and type of plantings, but in general a small residential rain garden will cost from $2-$5 per square foot if you build it yourself.

How much space do I need?

For the average residential lot, impervious surfaces total around 2400 sq. ft. A typical residential rain garden that captures about 25% of the runoff from a typical lot will be no larger than 60 sq. ft. (e.g. 6'x10'). To promote water quality, the goal is to capture the first ½” to 1” of a precipitation event within the rain garden.

How long does it take to build one?

Once you have selected the appropriate site, evaluated the soils and designed your rain garden, a rain garden can typically be constructed within a day or two. Remember to call KY 811 at 800-752-6007 before you dig, it's the law! Contact KY 811 at least two to three days prior to digging, they will come out and mark all underground utilities for free (or will advise you on who to contact, such as a local utility, to assess the site).

Where can I find more information about how to design and construct a rain garden?

View Residential Rain Gardens: Design, Construction, and Maintenance to learn more about how to design and construct a rain garden in your yard.