Tree roots have been known to upset or destroy the pipes in a septic system or even a septic tank. Tree roots naturally grow towards water supplies and nutrients that are in the soil surrounding the pipes that lead from your home to the septic system. This moisture will cause the tree roots to expand and form a spiderweb-like root system that will invade a small crack or tiny hole in the piping. Roots have been known to crack or crush the pipes and penetrate the septic tank.
If you have a tree planted near your septic system, you may want to watch out for a couple of tell-tale signs that you have a root problem:
Poorly draining toilets and sinks
The roots of your tree will grow towards the moisture in the pipes, causing a blockage. Your drains may empty more slowly than usual, or your toilets are not flushing everything, and it takes two or more flushes. Plunging the sinks and toilets will probably not help. If it does, the effects will be short-lived. You may want to call an expert who can inspect your pipes with a camera.
Unusually green vegetation over the leach field
If you notice your grass or ground covering is greener than normal, water could be seeping thru a cracked pipe and settling over the leach field. While this causes unsanitary conditions for humans, your vegetation will love the nutrient-packed water. The greener ground cover may or may not be growing close to the tree roots that are breaking the pipes.
A spongy texture or a soaked lawn
Sponginess, or if you notice areas of water in the lawn that are not draining, could be another clue that roots are blocking the leach field pipes. If the blockage is severe and the water has nowhere to go, it will overflow near the tank. Eventually, the ground becomes soft and muddy. If the problem is severe enough, pools of untreated water begin to form. This may be especially noticeable after a large rainstorm.
Odors
When water percolates into the leach field, there aren't any odors as the soil acts as a filtration system and absorbs them. If you smell something, it is often a sign of backup or leakage due to a tree or shrub root causing a blockage. Odors are the result of untreated water that pools under the ground surface. By the time you notice them, it has already become a serious problem. If you notice any odors near your house, it is probably caused by breakage in the waste line from your home to the tank caused by a root of a nearby tree. Remember, shrubs planted too close to your system can also cause these problems.