The simplest thing you can do at home to prevent pollution

For the environmentally conscious homeowner, there’s no shortage of creative ways to manage stormwater runoff. Raingardens, rainbarrels, trees, dry wells, French drains — there are all kinds of ways to capture and treat runoff at home.

But what if you’re not much of a landscaper? Or maybe you’re renting a house and your landlord doesn’t want you digging up the yard?

No worries. The simplest solutions are sometimes the best. And the simplest, lowest-cost way you can help protect local rivers and lakes from pollution is by redirecting your gutter downspouts to a vegetated space.

Why does this matter? Because during a rainstorm, your downspouts act like miniature stormsewer pipes. They take the rainwater that lands on your roof and send it gushing out onto the landscape. And where that water ends up can make a big difference for the environment.

Polluted runoff flowing into a stormdrain.
Stormdrains provide a direct connection between urban streets and surface waters.

If the water lands in a spot where it can soak into the ground, no problem. But if it lands somewhere hard and runs over that surface, it picks up pollutants along the way. This polluted runoff flows swiftly to the nearest stormdrain, which is a direct pipeline to the nearest river, lake or wetland.

Our water quality monitoring team spends its days chronicling the results of this polluted urban runoff. Those results include a near-constant stream of trash, sediment, phosphorus, nitrogen, chloride, fecal coliform bacteria, heavy metals and other pollutants into the Mississippi River.

The MWMO does all kinds of projects, big and small, to treat and prevent this type of pollution. But you can also help this effort at home with minimal cost, and little-to-no knowledge required.

So here’s the goal: redirect your gutter downspouts so that the water goes someplace where it can soak into the ground. All you’ll need is a good spot for the water to soak in and a downspout extension to get it there. If you can manage that, you will be helping do your part to prevent water pollution.

Just be sure to protect your landscaping and the foundation of your home with the following tips.

How it works — the basics

Clogged gutter.
In Minneapolis, a house with a 1,500-square-foot roof can generate 31,000 gallons of stormwater runoff per year.

First, some quick review: Gutters and downspouts are designed take rainwater and melting snow that runs off of your roof and direct it away from the foundation of your house. This prevents flooding in your basement and protects the house from water damage. It also protects the landscaping around your house from being eroded by constant dripping.

The sheer volume of runoff handled by these gutters and downspouts is a force to be reckoned with. A modestly sized home with a 1,500-square-foot roof will generate approximately 1,000 gallons of runoff per 1-inch rain event. Since Minneapolis gets nearly 31 inches of average annual precipitation, a single home is capable of generating up to 31,000 gallons of stormwater runoff each year.

Your goal, as an eco-friendly house-dweller, is to soak as much of that water into the ground as possible. The soil will filter out the pollutants and the water will move downward until it reaches the water table. As a bonus, any plants, trees or other vegetation in the area will soak up a portion of the water to use as fuel.

Finding a good spot

Downspout discharging onto sidewalk
An example of a downspout discharging partially onto a walkway. Simply moving the downspout a few feet (or even inches) could reduce the amount of runoff leaving the property.

While it’s obvious that stormwater can’t soak into hard surfaces like pavement, some might not realize that it can’t soak into compacted soils or those with a high clay content either. For this reason, you’ll need to figure out whether you’ve got a good spot in your yard for soaking up stormwater.

Are there spots where water pools in your yard during a rain event? Can you see runoff visibly coming off of your property and reaching the street? What happens to the water after it leaves your downspouts? After you’ve taken stock of what happens on your property when it rains, it’s time for some experimentation. As you factor in things like walkways and landscaping, look for a place that the water can infiltrate — preferably a grassy or vegetated spot. Make sure a downspout extension won’t block foot traffic, and then head to your local hardware store.

Metal downspout extended to a grassy area.
An example of a downspout (at right) aimed at a low, grassy area. Note that the location is well away from the home’s foundation and does not block any walkways.

There are a wide variety of extensions available, and most are self-explanatory and easy to install. Plastic extensions are handy because they’re flexible and require no hardware; however, they may not be as durable over the long term as some of the alternatives. If you’re a little more aesthetically particular, you can also find directions online on how to install a metal downspout extension.

If you’re not sure how well your ground will soak up the water, you have a couple of options. One is to do an infiltration test. This can be performed at home with no special equipment. You can find detailed instructions online, as well as complete how-to videos like this one. You can also try a mason jar test to help determine the content of your soil.

Be sure to avoid sending your redirected runoff near the foundation of your house. A little common sense will go a long way toward keeping your house safe from water intrusion, but if you’re not feeling very confident, you can also try enlisting help from a local Master Water Steward.

That’s a lot of information about a pretty basic concept, but remember: this is the lowest-hanging fruit when it comes to managing stormwater runoff in an eco-friendly way. If you feel like you’re ready to take the next step, you can combine downspout redirection with some creative landscaping (see the photos below). You can visit our landscaping ideas section to learn more.

Downspouts leading to a dry creek bed.
The downspouts at this South Minneapolis church are directed to a dry creek bed, which carries the runoff into a raingarden.
Flexible downspout extension and dry creek bed.
Similar to the above photo, a flexible downspout extension (which has been partially buried) leads to a dry creek bed and ultimately to a residential raingarden.

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