Best way to add capacity to leach field

[gw3]

Hey everyone, I have a couple questions--

I live barely above the water table and the leach field is 30+ years old. It gets slow, 20 inches of rain this month haven't helped and we also had a pressure-flush of a clogged pipe that added way too much water to the field.

I've decided to add another lane of drain pipes. It makes sense where we live, on the coast, 11 feet elevation, surrounded by holding ponds, rising ocean, thinking long term.

The soil is pure sand. No dirt at all. It is literally a dune.

Q 1: When I lay the gravel, should I put a barrier underneath it? I assume the gravel is still a good idea even in just sand.

Q 2: I plan to put the spur upstream of the D-box, the way the yard lays out it should be super quick and also extend the area that has "grass," best part is there are no roots there. Any problem with upstream if I make sure to keep it level? I like the idea that it will relieve pressure on the older field and let it heal during the hotter months.

Thanks

 

[Zanne]

gw3, I don't know what state you live in, but as far as I know, anything you do involving the septic tank and leach field has to be approved by the local department of health/sanitation. They will want you to set up an appointment for a percolation test and then they will write up a slip saying what length you need and where it can run. Then you will have to contact a licensed installer for field lines and the inspector will have to come out to look at it before it is buried to make sure it is done properly.

Where I live, the lines cannot exceed 100 ft per run and can not be deeper than 12 inches.

I had my whole system redone a few years back and was told I needed about 300 feet of lines if I had gone with perforated pipe and gravel. Instead, I went with Infiltrator systems (which was cheaper in the long run).

They come in 4ft segements about 2ft wide and just click together. The segment joints pivot so they don't have to be in a straight line. And they have little end caps when the line terminates. Instead of needing 3 of the gravel ones, I ended up getting 2 infiltrator lines installed.
Here are pics from my installation

Segments stacked up

Installers digging the trench

Health inspector examining the work

End cap

 

[frodo]

if you have water table problems you might look into a sand hill system.




contact your local health department for a perc test and a engineered system recomondentation