Minimum height for laundry standpipe?

greetings… it there a minimum height for a standpipe or laundry box? i cant find anything specific in the UPC. i understand that its got to have enough drop to drain properly. ive just finished a 2nd floor laundry and have it installed 30" high.

its not as high as id like, but i cut the wall out on the other side for plumbing access and wanted to keep it under the wainscotting to be hidden easilly.


Standpipe diameter >=2”, height 30-48” , trap <= 12” above floor.

(It’s in P2706.2, I think, but I don’t have a reference handy).

Also, check height relative to overflow point of laundry tubs - if it’s lower you can overflow standpipe if tub is on same drain line and kine clogs downstream of sink and standpipe.

great! thanks Michael! i have a 30" tall 3" dia standpipe reducing to a 2 1/2" trap. the washer is a water saver so im not worried about overflow, it only uses a couple gallons. and there wont be a tub in there.

the appliances are coming in 12 days, i cant wait. we have never had new appliances, always hand-me-downs.

Not sure if Ohio Plumbing Code is based on the IRC plumbing codes, but under IRC the Minimum height of a washing machine standpipe above the trap weir is 18" and the maximum height is 42".

That said, your current standpipe arrangement is illegal and a code violation under ALL plumbing codes.

The reason:

You cannot reduce the size of a drain as it flows downhill.

If you have a 3" standpipe reducing to a 2 1/2" trap, you create a restriction point, especially for water discharging under pressure.

You need to either run the entire drain in 2 1/2" pipe or 3" pipe.

You cannot have a 3" pipe reduce to a 2 1/2" trap.

Very bad problem.

Please fix it.

Hum… perhaps I have it wrong, but I thought with as 30" above the weir, as illistrated at pp 47 here:

As I understand it, it’s min 30" above the finished floor and min 18" above the wier, as noted on pages 46 and 47 here:

Do I have this right?


The 30" minimum height requirement is for the standpipe above the trap weir and only applies when a laundry tray drain connects directly to a washing machine standpipe.

The 30" does not apply to height above the floor.

There likewise is no height requirement of the trap above the floor in the national model code. The trap can be located below the floor. The only requirement since 2003 is that the traps of all standpipes be accessible for rodding.

Otherwise, the minimum height of a stand alone standpipe above the trap weir is 18" in all cases under the IRC 2000 through 2006.

Minimum standpipe size is 2"

Local codes may vary and further restrict national model codes.

OK, what am I missing here:

P2706.2 Standpipes for automatic clothes washers shall extend a minimum of 30 inches (762 mm) and a maximum of 48 inches (1219 mm) above the finished floor. The trap for a clothes washer shall be installed at a maximum of 12 inches (305 mm) above the finished floor. Access shall be provided to all standpipe traps and drains for rodding.

thanks for the replies. the washerbox has a 2" drain inlet, but the reducer is just an inch or so from the top. after the washer gooseneck goes in, it won’t hurt.

I just thought of something else. hope its not a dumb question. what about a lint trap on these washerboxes? I’ve seen a million and never thought about one.