The fastest way is to rent a trenching machine from a local tool rental.
Gutter drain pipe depth.
This is a great demolition hammer tool to chip out rotten concrete.
The solid particles may eventually clog the pipe.
Since my in ground pipe ran right past the garage i had the garage downspout dump in as well.
This trench would follow the natural contour of the ground.
If you have hard clay soil or rocky soil you can use an electric hand held demolition hammer tool to dig a trench.
In many instances i would dig a trench only 16 inches deep.
Buried or underground roof drainage downspout defects clogging overflowing holes corrosion leaks that cause wet basements or crawl areas proper installation of buried downspout extensions proper installation of french drains seepage pits at flat sites gutter downspout defects cause wet basements crawl areas questions answers about installing maintaining repairing buried roof.
If you live in a cold climate trapped water may freeze and burst the pipe.
I usually dig a trench about 12 to 14 inches deep for downspout drain lines.
Drain pipe slope maintaining a depth of 12 to 18 inches is best for drain pipes but the depth of the pipe may vary in order to maintain a downward slope which is critical for proper drain functioning.
The trench should be at least 6 inches wide and slope down slightly 1 to 2 inches per length of pipe so water drains away from the downspouts.
Depending on the trench length and more important the type of soil digging the trench with a shovel can range from relatively easy to downright impossible.
To do this i cut the black corrugated pipe added a t and aimed the pipe upwards to the downspout.