French drain over/across septic lines

[shade2u2]

Is it a good or bad idea to lay or run a french drain over spectic lines. It would be appoximately 8" deep and run perpendicular to the septic lines which run 24" deep.
Or, how about just a drain line without the perferation to move a little water to a more desirable location that would run above the septic line in a similar way?
I did post this on CountryByNet also...

 

[chucko]

I would think that it would be best not too do it at all but some times what is best can't be done so my thoughts are I would use the solid pipe around your drain field area to keep the poop in the drain field.

 

[CTyler]

If you talking about the line to the septic system then I don't see an issue.

If you talking about your drain field/leach lines then no I wouldn't do that.

I don't think crossing it with solid pipe to take it else where would be an issue either. You'd want sufficiant distance so you dont saturate the ground near your drain field.

 

[mahlers]

Are you trying to keep your leech-lines from getting waterlogged during heavy rains? Do you have a spring near the leechfield, or do you have a drainage problem where water drains right over the leechfield?

In either of those cases, your best bet is to dig a deep trench (around 6') on the high-side of your leechfield, line the leechfield side of the trench with heavy poly-sheet, and put the perforated PVC in the trench with washed gravel and a grit barrier - and run the drainage line from the french-drain far away from your leechfield. That will help keep water from draining down into the leechfield and waterlogging it. You'll need to keep the french-drain far enough away from the leechfield so as to ensure that you're not running effluent through it. Usually six to ten feet away is 'safe enough' but your local codes will dictate.

 

[shade2u2]

My objective is to move ground run-off from an area near my barn to another spot that is downhill from my barn and on the other side of my septic lines. I either have to end the french drain at the septic field (probably not a good idea), run it across the septic field and dump it on the other side of the septic field, or try to route it around the septic field (which is difficult due the grade around my barn).
I may be able to run it across the line from the septic tank to the septic field rather than across the leech lines.

 

[chucko]

you surly don't want to end it in/near the septic field no matter what

 

[B7510]

Run a solid line across the septic field if you have to, but try and keep the discharge well away from your septic field. Our local health codes call for 10' minimum seperation between building drains and septic fields so if it were me, I would use solid pipe starting 10' before and ending 10' after the drain field.

 

[shade2u2]

Thank you for the help. /forums/images/graemlins/smile.gif
Now I have a question about the leech pipe. I see some that has "holes" in it and other that has "slits" in it. /forums/images/graemlins/confused.gif
Is there a difference? Which do I want?

 

[CTyler]

I used the perf pipe with the slits in it, keeps the road gravel from getting inside the pipe.

 

[B7510]

If you are running clean water into the pipe, then no real difference in the shape, its the overall area to get water into/out of the pipe that counts.

If you are bedding it in sand though you probably want tho get pipe "in a sock". Around hear it is usually flexible corrigated pipe that comes in a roll with the fabric already around the pipe. The fabric, or filter cloth, keeps the dirt out of the pipe and helps keep the roots out for a while too.

The typical around here is to dig a trench a couple of feet deep, put an inch or three of coarse stone in the bottom, lay in the pipe (with sock) and then fill the trench to the top to create the french drain. If its not clean sand you might also want to line the trench with filter cloth prior to filling with stone. THat keeps the finer particles in the dirt from plugging up the stone. THe two feet of stone does two things for you. First it will accept a whole lot of water quickly when you get the sudden gully wasther. Second, the water building up in the trench will create pressure to force the water into the pipe (put a head on it). You might not be able to get it very deep with the drain field crossing to contend with. Keep one end or the other easy to get to though, just in case you have to jet it out or run a root cutter through it in the decades to come.

At the outlet end you essentially do the same thing, but the stone filled trench "daylights" out the side of the slope to discharge the water. The end result is that you dont see the pipe and you can work it into the landscaping with large rocks, garden gnomes, ... What ever blows your skirt up.

Bottom line, water flows downhill, most of the time, and this is probably a lot more than you realy were asking ......