electrical and septic in same trench

[His200HerScout]

The trench for my electrical service to my soon-to-be-built detached garage is so close to my septic tank that the extra cost of running a drain to the garage is minimal. I think I should just put in a 4" pipe from the garage to the tank so I can have a toilet and sink in the garage.

Is there anything code-wise that prevents a 4" PVC pipe for sewage and a 2" PVC pipe for electrical service from being buried in the same trench? Do they need to be some distance apart? Anyone else do something similar?

For the water supply line, I think I'll just hammer in a sand point well at the garage. So water supply lines in the trench are not a concern.

Thank you!

 

[hblock72]

I ran everything (sewer, electrical, co-axial cable, and cat5 line) to my detached garage in the same trench with the blessing of the inspector. This was in NC though, so check your local building codes.

 

[GrantMLS]

yeah being michigan i would check with a local inspector.. michigan has some odd codes..

 

[kbs2244]

I doubt they will allow it.
Septic trenchs are always wet.
They will not trust the pipe joints to be forever water tight.

But it won't hurt to ask!

 

[W-Cummins]

I would not install them in same trench because

The line into the tank MUST have slope, too little it will not flow well, and too much, it will leave the solids in the line, neither is a good deal..

Also the installed depth of the electrical service/feeder for the garage is set by its ampacity and cover ( i.e. concrete). The installed depth of the sewer pipe is set by the depth of the tank and the pipe slope/distance to the tank. So in a lot of cases your wire is deeper than your sewer pipe ( at least at the start of the trench) and you should place the sewer pipe on undisturbed earth, or compact the trench bottom so that the pipe doesn't break when the trench settles.

William...

 

[His200HerScout]

I would not install them in same trench because

The line into the tank MUST have slope, too little it will not flow well, and too much, it will leave the solids in the line, neither is a good deal..

Also the installed depth of the electrical service/feeder for the garage is set by its ampacity and cover ( i.e. concrete). The installed depth of the sewer pipe is set by the depth of the tank and the pipe slope/distance to the tank. So in a lot of cases your wire is deeper than your sewer pipe ( at least at the start of the trench) and you should place the sewer pipe on undisturbed earth, or compact the trench bottom so that the pipe doesn't break when the trench settles.

William...

Thank you. That trench slope and depth stuff was exactly the kind of stuff I was not sure about.

Thanks to everyone else also.

 

[nate379]

Are you allowed to run a garage drain to the septic even? Some places don't allow it. I have no drain in my garage for that reason.

The thought on that I guess is if you spill oil or other chems into the drain you pollute your septic and possibly the ground

 

[Dragster Racer]

We don't have inspectors or code outside of towns in our county. For plastic pipe, I wouldn't see why not just follow the slope of the drain. I'm no expert for sure. The trench may be wet, but well casing is often wet too, and power supply runs down the casing next to the water pipe. Just some unoffical thoughts. We ran power supply along with water supply. Contractor had no problem with it.