How hard is it to move Cedar trees? Some fool planted them over the septic tank. I think they should be moved, but I have no clue as to how deep the roots are. The trees are 8 - 10 feet tall. Will they destroy the tank and pipes underneath?

I have never moved a cedar tree, but wouldn't think they would be much different than any other tree. An 8-10' evergreen is getting a little big to move by hand. Over the septic tank is not a good place to use a tree spade. You could try. Dig at least a 2' root ball and bind it up with burlap. Be very careful not to break the root ball. If the trees die, you won't be out much more than just cutting them down. I don't think you can leave them there.