Trap not integral with a fixture

The 3/4" PVC in the center is a discharge pipe from the hot water heater in a mobile home.

The incomplete 2 inch PVC P trap is hooked to the bottom of a washing machine standpipe that has a P trap above the floor already.

Would you call these either of these out, if you believe they were just trying to protect the flooring?

Mobile and manufactured are under hud rules first so…
Is it original?
What are local rules?
BTW I didn’t look at picture or read your post.

Now onto the question asked…

Use common sense.

The standpipe should have a trap and venting in the plumbing world.

This trap isn’t doing anything beneficial. This was probably for something that was never finished or the installer had to be a “moron”. Pardon my French.

Manufactured and Mobile can get complicated. Understand the rules first in the U.S. because tradesmen don’t like working on them because of the rules. You may want to consider not inspecting them “in my opinion”

My comment is getting winded and open to opposition.

HUD rules, local rules, even “park” rules etc. Play a part in how things “should” be.

This “should be” done over


That P-trap is an opening in the system. If there was ever a blockage downstream that crawlspace would fill up with water and the occupants would not be aware.

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Welcome to our forum, Clifton…Enjoy! :smiley:

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Repair time, eh?


@mwilles Martin is on it.

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You got it🙂

I reworded that because I thought he said a standpipe was connected to it from a washing machine. So I thought there was a hose or something in it. Can’t see much in that photo with the bad lighting and my bad eyes

This p trap branches off the washer standpipe.

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Thanks, that’s what I thought at first then I read it again then confused myself…Lol.
Hey I should start sticking with my first answers

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Sorry for the delay in replying to you. I’m studying to become an inspector and this was originally a photo of the TPR discharge pipe termination. I’m renting the trailer, and I did this inspecting without the owner or property manager’s permission or knowledge. I don’t the answers to any of those questions…but I’ll take your advice about not inspecting these…thanks for that tip, and the other help.

After reading your reply I asked the manager for a 2 inch pvc cap, and told her I needed to make a small repair under the trailer…I even showed her this photo. She kind of freaked out, and said she had to call the PLUMBER. She texted me by mistake a few minutes later about “…an open p trap under one of OUR trailers. One of the tenants is questioning it and whether it was legal for the discharge pipe to come through the floor.” To be fair I mentioned the discharge pipe in case I don’t hear it failing and get a huge water bill someday, but that wasn’t a hill I wanted to stand on. I figured I’d probably hear water running quick enough. The P trap would be such an easy fix though…and it would have to smell better at the very least. She was supposed to call me back and let me know what he said, so far…its still open and I don’t have the owner’s permission to fix it.

Thanks for the help.

Yeah, trailers are difficult because if the factory had the discharge going to Below the trailer it can be legal.
Some parks or specific areas state it has to go to the outside not under.
There are other people that know the rules a little better.
Best to have a plumber work on it and if you are renting don’t do anything in regards to electric, plumbing or hvac. Have the owner do it
Hope you can get this straightened out.
Best of luck

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Good idea. I don’t need to crawl around under that leaky sewage pipe…that’s their job. You’ve helped me a lot, thank you.

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Thanks for all the help on this. Whoever plumbed it, left the P trap open intending to drain the HVAC condensate line into it later. I removed the grid panel cover of the HVAC system looking for the missing condensate line since there is no penetration through the floor for it. With the panel off, I immediately noticed a circular wet spot on the floor beside the base of the HVAC unit. The discoloration of the wet spot covered about 12 square inches of flooring and a little of the wall.

The DWV water trap is being used ‘as the receptor’ for the appliance drain hose.
I would call it out.
A: The water trap seal require a 1.5 or 2’ inch riser or designed tail piece to accept dishwashers discharge hoses. The water trap seal is the problem.
2: The appliance discharge hose must be secured prior entering the receptor to insure it does not move. C: The appliance discharge hose requires a high-loop.
Please excuse my rudimentary explanation.

I disagree.
1: The physical trap is a water seal. The seal impedes odors, insects and vermin from traversing the DWV upstream.
2: This is not a washing machine. The amount of detergent and rinse water velocity and flow being discharged are not the same. Henceforth, the tall riser for washing machine stand pipes being ‘at least’ 18" inches long, but no more than 30" inches high (including off sets.)

In this case, the owner just left the P trap open. He INTENDED to use it as a receptor for his HVAC condensate line at a later date. Presently, the P trap is just an opening in the system…so I did call it out and ask for it to be repaired asap. The discharge and properly trapped standpipe from the washing machine is back in the main sewer and drain line, and should probably have not been mentioned at all…since this trap branches off that main sewer line. Sorry if that wasn’t clear.

Since there is no appliance hooked to this open P trap, there was never any water in the P trap to create a seal with…unless of course the sewer had a blockage and then backed up enough to fill the trap with sewage that would have then leaked out as well. Either way…any water seal would have evaporated a long time ago, since there is no water entering the trap now.

You did the right thing. The P-trap is doing absolutely nothing. Some have made comments that the water seal will keep vermin out and sewer fumes in. That trap seal will be evaporated in a month. It needs to be removed and capped.

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I use mineral oil for floor drains, etc. that I don’t want to evaporate.