HELP - Planting trees near septic tank

blkhawk661 · May 06, 2012, 06:06:27 PM

I dug holes for trees 65 feet down the hill from the septic tank hatch. I ended up nicking the plastic piping in 2. I'm pretty sure it was the infiltrator dome. The grey plastic was less than 2 feet deep and I only scraped the circumference for a distance of less than 8 inches of the pipe.

I went ahead and planted the trees, but I am having second thoughts. Based on where the grass grows faster, I'm a good 40 feet from where the majority of the drainage occurs.

i feel 90% certain the septic will be fine, but i would really appreciate some reassurance from some professionals. I'd also appreciate insight on the idea of planting a few more frees 10 or so feet further down.

The increased grass growth is within 25 feet of the hatch. I have pics but can't figure out how to post (too new member?)

The hill is pretty darn steep. Easily 20 degrees. I don't see dirt going up hill. So i suspect clogging will be minimal.

Additionally I found out that the city will be offering sewage in my area in the next 5 years.

The septic was installed in 2000.

The nicks in the domes are both less than 4'' x 8". The one was barely hit.

Many thanks in advance

alex trent · May 06, 2012, 07:19:36 PM

Dont fret about that. Worse has been done and worked fine.

May 06, 2012, 07:35:27 PM

what about more trees further away? any way I can determine where the field stops so I can plant more? Or should I just not plant more because of additional risk to the drainage system?

alex trent · May 06, 2012, 09:00:24 PM

Non-technical apprasiel..

Past 100 feet like it's not there. Plant away.

Squirl · May 06, 2012, 10:56:41 PM

Um. Are you planting trees in your leach field? If you hit the infiltrator you are in the leach field.

http://www.pubs.ext.vt.edu/426/426-617/426-617.html

QuoteDo not plant these near a leach field unless you are prepared mentally and financially for the possibility of needing to install a new field sometime in the future.

QuotePlant trees as far away as possible from the drain field.

I was warned when I was planning mine with an engineer, plumber, and building inspector, lines should be at least 15 ft from trees.

May 06, 2012, 11:54:22 PM

Keep trees away from drain fields and springs. Roots will over take both and basically destroy.

alex trent · May 07, 2012, 06:56:26 AM

As "far away as possible is a pretty loose instruction". That includes the next county where you own property. 100 feet past the field is plenty...in fact 15 feet is enough. All but the biggest of trees do not have roots much past that.

I had a system in NJ that ran between a small grove of medium size Oak trees... 10-15 feet from about 7 trees and 21 years and still works fine. In NC ran a field right along a mixed hardwood forest...maybe 10 feet from the edge. Worked for 10 years before I moved.

A lot of the warnings depend on the type of tree and the soil and other things and are cautionary rules of thumb which are not hard and fast rules, so if it makes a lot of sense to plant close, it is likely to be OK. Most make more of this than needs to be.

I would not plant right in the field unless you are going to give it up real soon or have some of the local variables in hand....but adjacent to it is OK. If you are going to go to sewer and abandon the field, does not matter as roots do not take over over night. Be good to have some trees started.

flyingvan · May 07, 2012, 09:02:30 AM

While working with the local septic engineer to plan out my infiltrator system, he said in spite of all the warnings, after 30 years in the business he'd never seen trees damage a system---he even planted trees in rows right down the centerline between courses.
Infiltrators are very different from perforated pipe in a way that's important to your question----they aren't a continuous run that if you breach it in one place no effluent will get past that point. Instead, the first course will saturate, then a crossover pipe will start bringing effluent from the top of the first course over to the next. When the next one saturates, it'll come off the top over to the next, and so on.
Since you have an idea where your courses are, you can dig down to that course where the grass is growing green and add another bridge to the next course. Sometimes the runs have a high spot and effluent accumulates in a low spot, so adding a bridge at a lower point, if there is one, will bring the effluent over to the next course better.
I have never seen gray infiltrators---only black. Could be a regional thing.

You can see the 2 1/2" pipe coming from the septic tank dumping into my first course. Here you're required to have 100% reserve field available. My first course was only going to be 10' with the remaining 90' for that run part of the reserve; I went ahead and installed the entire 100' run so I wouldn't have a short saturated run right next to the cabin, if that makes sense. At the far end you can see the pipe coming off the top to feed the next run. Note that sometimes the pipes don't come off the top but off the endcaps a little lower.

Here's a view of my field all dug up ready to fill in. It's ideal---decent slope, south facing, good soil.

I hired a helper to hold the story pole so I'd get the courses perfectly level. The goal was, looking at the trench---If it were to fill with water where would the water go next? (actually this was the final course which in all likelyhood will never see any effluent. I've got over 300' of infiltrators for a tiny one bedroom cabin

blkhawk661 · May 08, 2012, 05:59:07 PM

Thanks guys for all the input. I'll monitor the soil closely and since the trees are only 5 ft I easily remove in the next couple years. I'll leave them be for now knowing that I may need to add more drainage later. My feeling is that the slope will allow me get away with this.