Rain Gardens

A rain garden is a depressed landscape feature that captures rainwater runoff from roofs, driveways or other hardscape surfaces then slows and cleans the rainwater runoff and allows it to sink back into the ground.

Rain gardens can be a low-cost, effective, and beautiful way to reduce the amount of stormwater run-off that may wash pollutants from your property into storm drains which then drain into our local creeks. Rain gardens can be filled with native and drought tolerant/wet tolerant plants that provide seasonal color, texture, and provide pollen and nectar for bees, butterflies, and hummingbirds. Below is a list of benefits rain gardens provide.

Rain Harvesting 6

Benefits of rain gardens include:

  • Helps stormwater infiltrate into the ground rather than into local creeks
  • Promotes groundwater replenishment in soil conditions that allow for infiltration 
  • Reduces the amount of pollutants from roofs and hardscape from draining into local creeks
  • Slows stormwater runoff; decreasing peak storm water flows and therefore reducing creekside erosion
  • Helps clean the stormwater as it is filtered through the soil
  • Adds an aesthetic landscape feature with many planting and design possibilities
  • Plants used in rain gardens can promote native habitat and food source for hummingbirds, butterflies, and honey bees

Why rain gardens?

Stormwater carries pollutants to local streams, lakes, and ponds and may contribute to flooding during heavy rainfall events. A rain garden is a man-made landscape feature designed to capture and reduce stormwater runoff. Rain gardens are particularly important in urban areas because developed land (pavement, buildings, and compacted soils) increases stormwater runoff.

Things to consider:

Is my property suited for a rain garden?

Some properties are developed on steep hills and the homes were built with drainage systems designed to move water away from the property and into the storm sewer.  Rain gardens may not be appropriate for this type of property.

However, homes on flat or slightly sloped properties may be ideal for rain gardens.

    • Do your downspouts from your roof gutters drain onto impervious surfaces such as walkways, driveways or into a piped drain system?
    • Do you have an available garden location, particularly located downhill from a downspout or concrete area around your house?

If you can answer yes to the following two questions, then a rain garden may be right for you.

Will a rain garden integrate into the landscape design?

Rain gardens can be accommodated in almost any residential landscape. The goal of a rain garden is to capture runoff before it reaches a storm drain or water body. Ideally, a rain garden will be located between the sources of runoff and the runoff destination. The size, shape, and plants can be tailored to the location and the amount of water you want to capture. Remember that a rain garden will be periodically wet or dry, but should not hold water more than two to three days.

How much will it cost?

The cost will depend upon the size of your garden, plant selection, amount of mulch needed, and whether you do it yourself or request a professional. In general, a small residential rain garden will cost between $100 and $300, but could be much more if a contractor in required.

How long does it take to build?

Once you have determined the design of your residential rain garden, it can typically be constructed in a few days.

Caution Always call before you dig to ensure you don’t dig up a gas line, electric line, water line, cable line, etc.  Visit our Know What’s Below-Call 811 Before You Dig page for more information

What tools and materials do I need?

Common yard tools like shovels, a tamper or heavy object (like a cement block), and an inexpensive leveling device are all you’ll need. Other supplies include mulch for the garden basin and berm.

How much maintenance is needed?

Basic maintenance includes typical care for new plants the first year (especially regular watering during dry spells) and pruning, thinning and transplanting once plants are established and as the garden matures. Replenish mulch every two to three years.

So, if you think you might be interested in a rain garden…

Visit the links below to learn how to build your own rain garden.

Rain garden Links

Below are a number of fantastic links on rain gardens.  Note, many of these are from other states and all information may not be appropriate for our location.

Pacific Grove RainScapes
This website has a lot of great information on rain water harvesting, rain gardens, roof downspout redirection, and more. 

Rain Gardens and Vegetated Swales
This site provides information on benefits of rain gardens, how to build one and links to California plants for rain gardens

This Old House: How to Build a Rain Garden
This includes step by step instructions for creating a rain garden. Provided by This Old House

Rain Garden How-to Manual
This how-to manual provides instruction and calculations for creating a rain garden. Provided by the University of Wisconsin Extension

How to Build a Rain Garden in Ten Steps
This includes the basic steps in creating a rain garden. Provided by the Rain Garden Network

Sunset Magazine Best Plants for Rain Gardens
This provides a list of good plants for a rain garden. Provided by Sunset Magazine

Northern Virginia Homeowners Guide to Rain Gardens
This site provides information on designing and constructing a rain garden.  Provided by Northern Virginia Soil and Water Conservation District