A standpipe is the drain pipe behind a washing machine that rises about three feet above the floor. It may only be visible as a hole in a washing machine faucet box in the wall of newer homes. Although it seems to make sense to seal the connection between the washing machine drain hose and the standpipe, the plumbing code requires an air gap to avoid a vacuum-induced siphoning of the water out of the washing machine. The washing machine hose should be hooked into the standpipe and secured from backing out, but the small gap around the washing machine hose inside of the standpipe should remain open to allow air into the pipe connection to break any vacuum that might otherwise be created during draining. The photo above is an example of how not to do it, and the one below shows a typical installation at a faucet box with a zip-tie securing the hose into the stand pipe.

    Also see our article Frequently Asked Questions (FAQ) about Laundry Areas

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Here’s links to a collection of our other blog posts about PLUMBING PIPES:

• How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

• Can galvanized steel pipe still be used for new water lines in a house? 

• How can I tell if I have cast iron pipes in my house? 

• Why can't a sanitary tee be used for a horizontal-to-horizontal drain pipe connection? 

• What is the difference between green and white sewer drain pipes?

• Is a washing machine drain hose required to be secured at the standpipe?

• What are the abandoned pipes sticking out of the wall in my house?  

• What are the code requirements for plumbing vent terminations?

• What are the code requirements for layout of drain piping under sinks?

• What causes a gurgling sound when a bathtub or sink drains? 

• What is a "combination waste and vent" in a plumbing system? 

• What is a building trap?  

• What is a galvanized nipple?

• What are the pipes sticking out near my water valves?

• How do you accurately find a broken water pipe leak under the floor slab?

• What is the difference between water pipe and sewage (waste) pipe?  

• Is a hot water faucet handle required to be on the left? 

• What is a dielectric union? 

• What's that powdery crust on the pipe connections at the water heater? 

• If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem?  

• How can I tell what type of plumbing pipe I have?

• Why is there a flexible accordion pipe under the sink? 

• What is the difference between PVC and ABS plumbing pipe?

• What is the difference between water service pipe and water supply pipe? 

• Can you connect CPVC pipe directly to a gas water heater?  

    Visit our PLUMBING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.