Reusing abandoned Septic Leach Lines

[redman2]

For some reason, when the previous owners decided to install a new leach field ( chambers) for the house, they decided to abandon the old lines ( pipe & rocks), instead of using a diverter valve to alternate between fields. Old lines were installed in 1986, new lines installed in 2005. It's been almost 20 years and noticed a lot of water intrusion during heavy rains. Ever since we moved in this house I kept thinking about the fact that it will come the time to deal with the leach line replacement. At the same time, I keep thinking about the old field.... and I think it would be worth trying to locate the old lines and install a diverter valve to let the new field recover. I'd rather don't wait until the field will fail.....

I pretty much know where the old lines are ( sketch from 2005 installation + trenched and found the rock bed) but there is a potential issue: in 2008 there were Pepper trees planted on top of the section where the old leach lines were installed . Considering there was no effluent draining into the old field, by the time the pepper trees were planted, how bad can the damage be? Will it be worth the money to hire someone with an excavator to help locate and check condition of the old lines or most probably they are useless because of the root intrusion ( even dry)?

I spoke with a couple of septic repair companies about my hope to find and reuse the old drain field and their first thought was : they would be in bad shape due to root intrusion.

However, I've seen/learned about septic leach lines installed in the middle of the forest and that gives me hope that my pepper trees should have not caused more damage than a forest (with larger trees) . I hope this makes sense.

So the options are:

1-Locate and try to reuse the old leach lines. Exploration of the old leach field and installation of a diverter box would cost about $4,500 ( potentially max $3,500 just for locating and assessing the condition of the old field) but would re-use the same section of the yard ( save space and still leave room for one more drain field, if needed).
If roots are indeeed showing during a video inspection, will it be possible to restore them : cut /remove the roots with a jetter ,to make them functional again ? I am willing to cut the pepper trees ( and try to kill the stumps) if that will make the old leach lines last longer ( root free).

2- Install a new drain field ( pipe + rock) and a diverter valve. This would cost $13k-$15k and would take the last section of yard available.

I suspect that companies prefer to install a new system instead of trying to repair an old one. I am posting here hoping to hear from people who dealt with root intrusion and know the damage it can cause to a drain field .... maybe even restored root damaged drain fields. Were you able to recover such fields ? What would you recommend?

Thanks in advance!

 

[MicEd69]

Leach fields have a definite life. The sewage effluent drains into the soil. There are some solids that end up being "filtered" out by the soil. As more and more solids collect in the soil, the ability of the liquid to flow down into the soil is reduced. Once the soil has collected enough of the solids, the leach field becomes "blinded" and unable to "leach". At that point, a new leach field must be used. So regardless of the condition of the pipes, to try to use the old leach field is highly problematic. You can hire a company to come in and perform a percolation test to verify that the old field has no life remaining. I would not think the previous owner would have put a new leach field unless the old one had lived out its life.

 

[redman2]

Leach fields have a definite life. The sewage effluent drains into the soil. There are some solids that end up being "filtered" out by the soil. As more and more solids collect in the soil, the ability of the liquid to flow down into the soil is reduced. Once the soil has collected enough of the solids, the leach field becomes "blinded" and unable to "leach". At that point, a new leach field must be used. So regardless of the condition of the pipes, to try to use the old leach field is highly problematic. You can hire a company to come in and perform a percolation test to verify that the old field has no life remaining. I would not think the previous owner would have put a new leach field unless the old one had lived out its life.

Thanks for the reply! I understand and agree the leach lines have a life.... of continuous use. However, my understanding is that if left unused, the soil/lines will "recover" and can be used again.
I have no actual experience with this and not sure if this is actually what happens.
Based on above mentioned theory, I thought my biggest concern would be the root intrusion.....
Assessing percolation capabilitues of the old lines would be another item to add to the Option 1.

 

[MicEd69]

Assessing percolation capabilitues of the old lines would be another item to add to the Option 1.

That should be the first thing to do to see if the original filed is suitable for use. If the ground isn't suitable. no use in trying to clear the drainage piping.