How far away do shade trees need to be from Leech Fields/Drain Fields?

Question

It looks like we have 5 lines that run horizontally in our backyard....septic tank is close to the house so will not be an issue.

What we would like to do is plant a few shade trees, maple maybe but any suggestions would be appreciated, near the back of the yard that will provide some shade. I think I can get about 5 to 10 ft away from the last drain field.

We live in Charlotte, NC.

Thanks!

Answer 1

then maples are out, as their roots will seek water and clog the lines......... if you cannot get farther away, then the biggest thing you can plant is a standard, not tree-sized, crepe myrtle.... tops out at 12 ft or so, but doesn't go wide.... roots would be contained in your '10 ft'..... but that's not going to get you much shade....how's about a pergola?...

which direction in the yard will get you the most shade?..... is there a side area that isn't close to the  house or the neighbor that would be big enuff for a line of tall slender trees like Thuja,  that would cast afternoon shade on the house or the back patio area?....

if your whole backyard is filled with lines, you're going to have to skip the trees and go for a  different kind of structure to get shade.... a sail, pergola, gazebo, vine and trellis, screen planting, something other than shade trees.....the thuja make a barrier, fence-like scene, but can cast shade if in the right position .....

http://www.fast-growing-trees.com/ThujaG...

Answer 2

Think again.  Tree roots are horizontal and at least 2x and up to 5x the branch length.  So if that branch is 20 feet long, then the roots will be 40 to 100 feet long.  

I have put trees 20 feet from the outermost leach field line as I figured it would cause the least amount of damage to the system.  After 30 years the field failed, not from tree roots but from laundry and kitchen soap destroying the porosity of the soil.

Answer 3

You shouldn't plant them near a leach field.  Tree roots can  clog and damage your drain lines which will require you to install a new field at some point in the future.  If you want to plant them anyway, then at least plant them at the far end where it is drier.  Or plant them as far away as their expected mature height (this is equivalent to the mature root spread).

The website below has great information on this, including recommended trees.