# What Sewer Pipe Should I Use



## charlie58 (Apr 20, 2010)

I am installing a toilet and sink in my shop and am trying to figure out what material to use for the main sewer line. When I bought the place it had a 4" stub up for a toilet that also had a 2" tied in for a sink or vent then exited the slab about 3' from the toilet stub after being reduced to a 3" sched. 40 PVC. I have to run the drain about 80' from there to a septic tank that has a 4" hookup. I have a 11.5" drop/pitch from where the 3" exits the building to the septic tank. This is all that will be hooked to the septic tank.

My questions are:
1. Is 11.5" over 80' enough drop?
2. Should I run the 80' with 3" or 4" pipe?
3. Should I use "thin wall drain pipe", "thick wall drain pipe" or sched. 40 PVC?

All 3 types of pipe look like PVC and are sold at Home Depot. The only difference I can tell is the "drain pipes" have the collars made into one end of each pipe and the sched 40 does not. Any help would be greatly appreciated.


----------



## D'Brie (Dec 20, 2009)

I would use ABS instead of PVC, more forgiving. DO NOT use thin drain pipe for your sewer. If you use 3" pipe you'll need 1/4" drop per foot, use 4" and you'll need 1/8" per foot drop, 3" is more than large enough for your application. Try not to drop too quickly as the fluids will run faster than the soilds and leave them in the pipe. Make sure to use transition glue if you go from PVC to ABS. Good luck!



charlie58 said:


> I am installing a toilet and sink in my shop and am trying to figure out what material to use for the main sewer line. When I bought the place it had a 4" stub up for a toilet that also had a 2" tied in for a sink or vent then exited the slab about 3' from the toilet stub after being reduced to a 3" sched. 40 PVC. I have to run the drain about 80' from there to a septic tank that has a 4" hookup. I have a 11.5" drop/pitch from where the 3" exits the building to the septic tank. This is all that will be hooked to the septic tank.
> 
> My questions are:
> 1. Is 11.5" over 80' enough drop?
> ...


----------



## Just Bill (Dec 21, 2008)

1. as stated above, 1/4"/foot.
2. 4"
3. NEVER thin wall, that is for perimeter, gutter drains.


----------



## Alan (Apr 12, 2006)

I don't know about other local codes, but in oregon we are ALLOWED to have 1/8" per foot outside of buildings.

Don't use thinwall PVC as stated above, but you also don't need to use abs. Outside of the building you should be able to use 30/34 gasketed sewer pipe and fittings.


----------

