The first thing you want to do is conduct a visible repair. Visible repairs are done at the ends of the underground downspout pipe. They can be at the entrance near the foundation, or where the water exits. If any part of the gutter drainage system is damaged, you should be able to see it. If you do a visible inspection you should notice any cuts or areas of the pipe that need repair. Simply cut off the damaged section and fix it using the appropriate tools.
If you have to repair the pipe near the foundation you will be required to work close to the bottom of the downspout. You will probably have to detach the bottom strap that holds the downspout in place. The downspout will need to be moved out of the way while you are reinstalling your gutter drainage system. It’s usually easier to swing it parallel with your home as it gives you more room to work.
Pvc pipe can be a little more rigid. You may need to cut a section of the downspout to get it out of the way. Once you repair the rain drain pipe, you can slide the section of downspout you removed back on and reconnect it.
Usually when you are dealing with pvc pipe, it is better to hire a professional. Pvc pipe can be very unforgiving and can require a little more expertise in order for the product to hold up long term.
If the underground drain pipe is damaged at the exit point, you can just replace that section.
If there is no damage to the gutter drainage system at one of the visible ends, the first thing you need to do is locate exactly where underground downspout is. One way you can locate the drain is to stand at where the downspout goes underground and then find the exit point. Most underground drains are installed in a straight line. If you start digging directly toward the exit point you should be able to find the pipe. All underground pipes are straight, but you can try this option first.
If the underground drain system is too far underground you will need a different strategy. Here are two ways you can locate the area of your pipe that is damaged underground.
Wire and Detector
Use a wire with a metal attachment and run it all the way through your underground drainage system. If your wire hits an area that is clogged, you will know that you have likely reached the damaged area. Use a metal detector to locate the metal attachment that is attached to the wire being blocked by the clog. Now you will know where to start digging to make the repair.
Sound of Water Hose
Take a hose pipe and run it through your underground drainage system. It should eventually run into a clog or other evidence of a damaged pipe. Make sure the hose is turned on and the water is spraying with enough force so you can hear it from above ground. If you have someone helping you, one person can run the hose pipe while the other tries to locate the pipe.
Neither of these options are easy, but they can save you from doing a lot of unnecessary digging.
One you have located the area of the underground drainage pipe that is damaged, you will need to dig out a work area. Make sure the damaged section is exposed enough that dirt doesn’t go into the drain if you make one wrong move.
Repairing Inline Underground vs Visible Ends
The middle of an underground pipe is a lot less forgiving than an end piece. You can’t move the pipe around and it is not as flexible because so much of it is buried beneath the ground. When you have enough room to start repairing the underground drain, cut the damaged section out. If the pipe you are dealing with is pvc, the pipe you use to replace the area should be the exact same size. Connect the pipe using a rubber coupler and tighten them down.
Corrugated Pipe Repair
Corrugated pipe is much more flexible than pvc. Cut the section away a little bit more than the damaged section and replace it. Use heavy duty couplers that actually insert completely into the corrugated pipe. Exterior couplers disconnect from corrugated pipes easily and leak more. If the damaged area is only 6 inches, you are better served to go ahead and cut out a 2 – 3 feet area and use your new pipe and couplers to make a new clean area. This will prevent you from having more problems in the future.