We just moved to a new house recently and have a septic tank that is between a pine tree and an oak tree right off the back of our house. I hate the thought of losing the oak tree but have been told that we should cut the trees down due to problems of the roots getting into the leach field. Can anyone give me any advice on this? My husband is going to have the trees cut down this week but I wanted to be sure that we have no choice before doing so. Thanks!

Reply to post by Bonnie, on May 25, 2003 at 16:40:19:

The location of the septic tank is less important than the location of the leaching fields. The fields are beyond the tank. Still, tree roots are quite far reaching and likely go into the field as well.

The only time I have seen fields fail from tree roots an elderly couple lived in the house (this was mid 1950s when nobody had dishwashers and washing machines or jacuzzis) and really but very little water down the drains. So not a lot of water flushed through the fields. Tree roots got into the leach line at its first corner and effectively plugged it. A young family buys the house, diapers, kids to bathe, daddy has to shower, more dishes to wash... and all that water went down the drain and could not get past the clogged first corner.

The tree was removed (much to the dismay of the mommy), the corner cleared, and fields workd fine. At least three other trees surrounded the fields BTW all in the front half of 1/4 acre. Some years later when dishwasher added the fields were extemded by one lateral run which was carfeully placed within a tree root system aligned radially with trunk so no major roots transected. That was 30 years ago and still no problem.

This entire neighborhood is 1/4 ac lots with septics and trees all around.

So trees and fields are not, per se, a problem. If the fields are functioning properly and wet frequently roots do not seem to plug them.

Now, who gave you the recommendation? Is it a common problem in your climate and soil type? Are there indications of problems already? I'd get a second opinion or a third. Talk to more than one spetic system contractor. Talk to local health department. Talk to other homeowners with septic systems.

Reply to post by Bonnie, on May 25, 2003 at 16:40:19:

I live in a foothill community that is served 100% by septic systems. There are Ponderosa pines and California Black Oaks all around. Tree roots occupy mainly the first two feet of soil which is a red clay strewn with basalt boulders.
We had our entire septic field relocated about a year ago (about 35 years old). It was inadequate for family uses, as Scott mentions. The explanation given by local septic professionals was that the pores of the leach field become sealed by fine particulates, generally starting from the near end of the leach line. Gradually field loses absorptive capacity surrounding the drain pipe.
On the other hand, we used to live at another (very small) house with a septic system that failed for other reasons. First, the field wasn't large enough and was also very old, but also the pipe leading into the tank had been deliberately and crudely opened as a "cleanout" by someone, consequently allowing Silver Maple roots an easy entry into the pipe, which it filled.
If the lines leading into the tank and out to the field are intact, then roots will not get into them. In the field itself, the field may lose functioning for reasons other than root plugging. Tree roots generally are at a depth just above the minimum depth required of modern drain fields. Also, nothing lasts forever, including septic systems, and you might wish to consider the value of the trees before removing them.
Another thought: If the tank (and house)was put in after the trees were already there, some root cutting, tearing and soil compaction damage may have been done to them during installation (probably less damage the further away the trees are). So keep an eye out for signs that root injuries are affecting the trees' stability (such as decayed supporting roots and trunk)so close to the house.

Reply to post by Mark Goodwin, on May 25, 2003 at 16:40:19:

It is important to note, as Mark says, that the outlet from the tank and piping to the fields should be solid pipe with no place for root entry. But remember that the fields themselves must be perforated pipe to allow the water to leach away.

Also, trees like silver or red maple or willow are more liklely to tolerate low oxygen and constant water exposure and so invade pipes. Other species will not be such a potential problem.

And as Mark notes a system that is silted up will be less performance tolerant of any further plugging by roots.