How to Extend and Route Downspouts Away from Your Foundation

Water is the single greatest threat to your home's structural integrity, specifically when it pools around your foundation. Every gallon of rainwater shed by your roof has to go somewhere, and if that somewhere is a three-foot circle of soil right next to your basement wall, you are inviting cracks, dampness, and costly repairs. Routing that water away is one of the highest-return tasks in home maintenance. You aren't just moving plastic pipes; you are managing the hydraulics of your property to ensure that every storm leaves your foundation dry. Done well, your extension system will be nearly invisible, fully secure, and sloped just enough to keep the water moving toward the yard or a dry well.

1. Verify the grade first. Use a level to ensure your extension pipe slopes downward away from the house. Aim for a drop of at least one inch for every three feet of length.
2. Clear and compact the ground. Remove any rocks, heavy mulch, or debris along the route of the extension. Ensure the ground is firm enough to support the weight of the pipe.
3. Redirect water downward. Remove the existing bottom section of your downspout and attach a new downspout elbow pointing toward your intended route. Secure the joint with two sheet metal screws.
4. Join and secure the run. Slide your rigid or flexible extension pipe onto the elbow. If using rigid PVC or aluminum, ensure the male end faces away from the house so water flows over the joint, not into it.
5. Set up the exit point. Place a concrete splash block at the end of the extension pipe. Position the block so the water flows directly onto the center of it.
6. Verify drainage works perfectly. Use a garden hose to run water through the gutter system at the roofline. Watch the entire length of the extension to ensure there are no leaks and the water exits fully onto the splash block.