Home>Discussions>PLUMBING>Minimum height for washing machine standpipe
5 posts / 0 new
Last post
abernard
Minimum height for washing machine standpipe
abernard

What's the minimum height for a high efficiency front load washing machine standpipe assuming the P Trap is no higher than 12" from the Floor? General plumbing rule of thumb seems to be 36" from floor. I'm also reading suggestions of 18" above the trap weir as a minimum. Additionally I'm seeing that the minimum height should also be above the maximum water height in the washing machine drum to prevent siphoning. With older top load washers I can see where a higher water height would necessitate a higher standpipe and hence the old safe 36" height rule of thumb. But with newer front load machines it seems the water height is now lower especially if the machine is not on a pedestal. So if my trap weir is at 12", my maximum water height in the machine is say 20", can I put the standpipe height at 30" or can I get away with it being even a little lower? Reason I need it to be no higher than 30" is so that the entire standpipe box surround which includes the water supply lines is below the height of the counter that runs above the machines. Thanks.

A. Spruce
Re: Minimum height for washing machine standpipe
A. Spruce

Part of the reason for a high stand pipe is to create a reservoir for the discharge water to collect, because it is pumped out of the machine faster than it can flow down the pipe. Now, one could argue that with today's lower water use washers that a taller stand pipe isn't necessary, however, it's a risk that, IMHO, isn't worth taking because what happens when the drain line has some debris build up, not quite a clog, but enough goo that flow is restricted? If you guessed that the stand pipe overflows, you're correct. So what is worse, seeing the washer supply box or flooding the laundry room?

bill
Re: Minimum height for washing machine standpipe
bill

the code calls for a pipe 24-36 inches above the p trap. I always cut a piece of 30 inches,and glued it in the wall , then a 45 degree bend with a 6 inch pipe sticking out of the wall. Once the gyproc was in i cut it flush to the finished wall. \The drain pipe would be behind the washing machine out of sight /. For the water pipe i would put the shut off valves at 47 inches above the floor so that they were visible in case of emergency.

This was for the old machines with the new front loading this will change, Also for the old machines a 1 1\2 inch drainage pipe was good enough, However with the new machines the code is changing to a 2 inch trap.

sharon
Re: Minimum height for washing machine standpipe
sharon

Re #3

my standpipe is installed with the 45 coming out the wall, with a short piece of 2" pipe.  My washer requires the top of the pipe entrance to be 39" above the floor, but this one is only 34".

Question:  Is it OK to just add another 45 bend and go up higher to 39", which would add another 45 bend?  Or do I have to re-plumb the pipe inside the wall so it goes straight up, and then do the 45?

 

Miriam
Re: Minimum height for washing machine standpipe
Miriam

Hello Sharon 

how were you able to resolve this ?  I have similar situation 

thanks !  

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.