How to Prevent Water Pollution with a Rain Garden

How to Prevent Water Pollution with a Rain Garden | GreyDock Blog
Article Intro

Reducing water pollution is as simple as planting a rain garden.

When runoff water comes in contact with fertilizer, motor oil or trash, those pollutants can make their way into larger bodies of water. Luckily, there's a way to prevent much of this polluted water from getting into our ecosystem.

Enter: the rain garden.

Rain gardens allow runoff water to filter naturally through your yard’s soil—plus, they look beautiful!

Sound interesting? Keep reading to learn more about planting a rain garden.

What is a Rain Garden?

Think of rain gardens like functional landscaping. They’re small gardens that collect and filter runoff water through plants, mulch and soil. Once the water infiltrates the soil, it makes its way into the surrounding aquifers.

These gardens look beautiful while serving a good purpose. According to the Wisconsin Department of Natural Resources, a rain garden allows about 30% more water to soak into the ground compared to a conventional patch of lawn.

Rain Garden Diagram | GreyDock Blog

Don’t worry about mosquitos, either – the rain garden water drains quicker than the time it takes for eggs to hatch.

Rain Garden Benefits

  • Adds beauty to your yard
  • Creates a wildlife habitat
  • Reduces water pollution
  • Prevents home and storm drain flooding


When it comes to building a rain garden, keep these things in mind: placement, soil type, size and slope.


You’ll want to build your rain garden at least 10 feet away from your home. Anything closer could cause issues with your foundation.

Avoid spots where water currently pools after a storm. That’s a sign of slow soil drainage, which is the opposite of what you want happening in your rain garden. There are better drainage solutions to get rid of this issue.

Soil Type

The type of soil in your yard will determine how quickly water will drain through your garden.

Checking soil type is easy. Dig a small hole, fill it with water and take note of how quickly it drains. Sandy soil will filter water faster than clay-based soil.


Before digging a rain garden, you first need to determine the slope of the area. Rain gardens need to be level so water doesn’t continue to flow past the berm. The berm (a small hill made of dirt or sand) will be built on the opposite side of where the runoff flows from. You can define the outer perimeter of the garden with decorative stones or pavers, but soil works fine for smaller gardens. Defining the berm will prevent erosion and help retain water.


Keep an eye on the area where you plan to make your rain garden. Does a lot of runoff rainwater flow to this area? Adjust the size of your rain garden accordingly. Most residential rain gardens are 300 square feet and under. It’s more cost-effective and unless you’re in an extremely rainy climate, smaller gardens will do just the trick.

Rain Garden: Before and After | GreyDock Blog

Choose Native Plants

Native plants are accustomed to your local environment and won’t require much maintenance once fully grown. You can go to your local nursery and ask about native plants, but you’ll save time by using an online resource and having a list of your favorite choices ready to go. Enter your state and other specs (like size and light requirements) into the Native Plant Database.

Once you’ve planted the greenery, use about 2-3 inches of mulch to cover the area. Not only will it filter out large pollutants, it’ll also keep the moisture in and help prevent weeds from growing.

Residential Rain Garden | GreyDock Blog

Like any home improvement project, planning and planting a rain garden won’t happen overnight. The whole process from start to finish takes a bit of time and effort—but the environmental benefits are well worth it.

By planting a rain garden in your yard, you help reduce the amount of storm water treatment needed in your local community, create a habitat for birds, and prevent flooding around your home. Who’d have thought a small garden could be so beneficial?

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