Plumbing the 1 1/2 story 20x30

[joesvolcano]

We recently purchased the 1.5 story 20x30 plans.  In my area I must have a septic permit before they'll issue the building permit.  So... we're going ahead with the septic installation before we start on the cabin.  We're planning to use the pier/post foundation.

We don't see a plumbing page in the plans.  The question is, where should we have the main drain placed relative to the floor plan?  

[jraabe]

The layout of the supply and drain lines are site specific and determined by the location of water inlet and septic or sewer lines. This is why they are not on stock plans (or even most custom home plans). Plumbers only need the fixture locations.

Most plumbers will have the main sewer line take off below the biggest fixture load in the house - usually the main floor toilet. From there any other drains are linked up to this main trunk. The slope on this line needs to be approx. 1/4" to the foot for proper flow. Thus the inlet location of the septic tank needs to be properly located to align with this sewer line.

This is why most builders like to get all the drain lines installed and the main sewer line outside the foundation before placing the septic tank. It is usually one of the later things to get installed.

If you have to place the tank early in construction, talk to both an experienced local plumber and/or septic installer to make sure this will all work out properly on your site. There may also be choices that can be setup with the tank to allow for adjustments.

And, of course, getting a septic permit first doesn't mean it has to be installed first.   (Your building department doesn't want to issue a building permit on land that won't perk.)

[joesvolcano]

Thanks for the info... we're learning!  Guess we should start the process of getting the building permit now.

[jraabe]

Yes, the permits are the fun part!  

Then, there is always the Glenn route...

[bartholomew]

If the septic field is near the building site, it's best to install it after building. It's not a good idea to have vehicles, especially heavy cement and delivery trucks, driving over the field.

[Amanda_931]

Yep--some friends have that kind of expensive damage to fix.  

[glenn-k]

Then, there is always the Glenn route...

In my old age I do sometimes forget to ask.