Relocated Washer Drain

[a12vman]

I am going to try to explain this issue without including a photo.

I am moving my Washer/Dryer Hookups ~ 12 Feet to another room on the 1st floor of my house. I was in the basement last night looking at how the 2" PVC drain would be moved. Currently the drain comes down through the floor to an elbow just below the Floor Joists. From there it runs for 10' pitching toward the main septic line(already tied in to the lowest point) going out at a rate of 5 inches over 4 feet.

So my question is, what is the smallest pitch that is acceptable considering that it is a 2" drain and that it needs to travel ~22 feet to get to the main drain line? I want to avoid notching out the Floor Joists if possible. Any alternatives?

Thanks In Advance, -a12vman

[Speedy Jim]

1'4" per foot will work just fine. So, you will have approx. 6" drop over the run. Consider putting a WYE fitting in the run for a cleanout, JIC.

The P-trap will need a vent connection (of some kind) just downstream of the trap.

Since this install is on the 1st floor, would a drain pan under the washer be appropriate in case of spills/flooding? Now is the time...

Jim

[a12vman]

I didn't follow. My total run is ~ 22 Feet. I only have ~ 6" of fall to work with over the 22 Feet. With only 6 inches, I would hardly have any fall. Am I missing something here?

As far as the vent goes, can I get away with adding an Air Admittance Valve? I don't have a vent stack anywhere nearby.

Instead of a drain pan I am using a recessed washer box with a solenoid that shuts the hot-cold valves when the washer is not in use. It also has an integrated leak sensor that I will place on the floor near the washer.

[Speedy Jim]

6" of fall over 22 ft gives roughly 1/4" per foot, which is acceptable.

P5 shows slope for one application.

Fig. P6 shows install of air admittance valve in relation to trap. Whether you can "get away" with it depends entirely on your local inspector.

Fig P7 Combo vent does not apply to your situation.

Jim

[a12vman]

Very good reference, thanks for the information!