Underground Downspouts Move Water Discharged From House

Some homes must run downspout water out towards the neighbor’s house. It looks ugly, and when the tube falls off, the basement floor gets wet. A solution is to direct the water into an underground discharge out to the lawn and eliminate the visible pipe or splash block.

Mr.Hardware.com has an ‘underground downspout’ that carries water away from the house and uses pea gravel in a French Drain. It filters leaves and debris from entering the pipe and has a cleanout at the end.I recommend using an above-ground filter where the house downspout connects to the underground system to prevent filling the underground pipe with leaves and debris. The filter will allow most of the leaves to slide off onto the ground as the rainwater drains into the underground downspout.

This filter connects to a 10 foot by 4 inch PVC pipe buried about 8 inches deep. I pitch the trench away from the house 1 to 2 inches for every 10 feet. This keeps the trench from having to be too deep yet gets the water away from the house.

At the end of the trench, I dig a posthole and fill it with pea-stone or crushed concrete to absorb and disperse water into the earth; this is a French Drain. The depth of the posthole is determined by soil conditions. The more dense or clay-like the soil is, the deeper the hole should be, usually 3 feet is sufficient. Fill the posthole with the stone to be even with the bottom of the trench.

I put a tee at the end of the underground pipe and wiggle it into the stone. Cut a short piece of PVC pipe to extend the top of the tee up even with the ground and insert a 4-inch strainer into the top. Water will drain down into the ground through one arm of the tee, while overflow water will go up through the strainer. Remove the strainer periodically to cleanout leaves and debris.

Use any remaining stone to fill around the tee and strainer and backfill the trench packing the dirt as you fill. And save the sod off the trench you dug. It will be invisible after a couple of weeks. Underground downspouts are effective and attractive.

Plan. Start by collecting all tools together, and buying the supplies. Do it right the first time. It took me 1 hour to do mine.