Where do I run the vent for a washer installation?
Routing the plumbing vent incorrectly or using the wrong fitting can render the washer vent completely useless. Using the proper fitting, such as swapping out an improper sweep for a sanitary tee, ensures the drainage and venting system works correctly without failing code or causing backups.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Draining through the floor, adding a santee to the trap, and continuing the vent through the attic or roof.Did this help you?
- 2Using an AAV (Air Admittance Valve)Did this help you?
- 3Swapping out the long sweep for a regular sanitary teeDid this help you?
- 4Flipping the trap aroundDid this help you?
- 5Leaving the unconventional plumbing fittings in place if it does not leak and drains properly.Did this help you?
- 6Cutting the pipe near the wall, installing a new trap adapter, and shortening or rotating the disposal elbow to adjust the elevation.Did this help you?
- 7Running the washer hose to a floor drainDid this help you?
- 8Running the washer to a cleanoutDid this help you?
- 9Installing a laundry sinkDid this help you?
- 10Installing a washer standpipeDid this help you?
- 11Calling a professional plumberDid this help you?
- 12Using hose clamps on the HVAC drain lineDid this help you?
- 13Getting a disposal tubular tee kitDid this help you?
- 14Using a low profile version to match the height of the disposalDid this help you?
- 15Offsetting the PVC/ABS piping and pointing it away slightlyDid this help you?
- 16Discharging the washing machine indirectly into a utility sink to keep the drain line size at 2 inchesDid this help you?
- 17Routing the washer drain into a utility sink instead of its own dedicated pipeDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Unfortunately, the garbage disposal is directly on the way of the wall pipe, so I put this together in a pinch and after looking at it again I don’t think it’s correct.”source ↗
“You spoke of bringing things up to code. I believe a laundry drain line is by code not allowed to be shared w other fixtures.”source ↗
“At least where I am in the US, it has to upsize to a 3" once there is a second fixture on the washing machine drain line.”source ↗
“Standpipe doesn’t look long enough. Also 1.5 is fine for the vent didn’t need 2””source ↗
“Stand pipe is too short, its gonna back up and overflow.”source ↗
“Oh yeah. That's all wrong.”source ↗
“Wrong tee makes the vent useless.”source ↗
“Swap out the long sweep for a regular sanitary tee”source ↗
“Looking for help on setting up the drain for the new sink.”source ↗
“Found out when removing our old sink that the drainage for our hvac system drains into the drain for the utility sink (pipe on top coming out of the wall).”source ↗
“Most laundry drain fixtures must tie into 3” before catching any other drain.”source ↗
“Stand pipe needs to be at least 18 inches for laundry, but preferably closer to 24 or you might get soap bubbles overflowing”source ↗
“I’m doing a small addition, moving my washer into the new construction, and I’m not sure where to run the vent.”source ↗
“We recently bought this 1937 house and can't figure out how to drain the washer.”source ↗
“I have very minimal plumbing knowledge and experience, but I've been googling all morning and both of those answers seem incorrect.”source ↗
“Sorry my ignorance but still need help configuring the drain! Haha”source ↗
“The second after installation and realizing the drain doesn’t line up”source ↗
Where this came up
People with this problem also raised
- 3How to tie in a vent line and shower drain in tight spaces
- 2How to route a plumbing vent offset around obstacles
- 5How to vent a relocated plumbing sink or drain
- 7How to figure out correct plumbing and venting requirements for a remodel
- 3How to install a vanity over floor pipes in a tight space
- 9How to hook up a dishwasher drain hose under the sink