Since my in ground pipe ran right past the garage i had the garage downspout dump in as well.
Bury your gutter downspout.
For the garage i used a downspout adapter without a leaf guard since there aren t trees close enough for that gutter to get clogged up.
Start laying your drain pipe by attaching a 90 degree angle pipe to the gutter downspout.
Take a drill and remove the old screws.
Now time to screw them into place.
Then remove the angle connector.
Repeat the similar procedure for the other end of the angle to connect it to the ground pipe.
To do this i cut the black corrugated pipe added a t and aimed the pipe upwards to the downspout.
Inspect the ground above the buried downspout after the first two or three substantial rainfalls.
Cover the inside of the fitting with pvc cement and push it into the lower end of the gutter downspout.
Map your downspout burial route check local rules for drainage regulations and contact your local utility offices before you dig.
Have your downspout extension and connector together then place on your gutter.
Use a garden spade to cut.