Unidentified plumbing

This drain/pipe was under a modular home and I was unable to determine what it was to. Any help is appreciated.

Thank you

Is the water heater directly above this pipe? If so that could be the TPR extension pipe.

The TPR extension pipe must terminate in a location that is readily observable by the occupants of the home.
If the water heater thermostat fails to turn off at its temperature setting and continues to heat the water indefinitely, the TPR valve will open and let the overheated water out; but, if the termination of the piping is not readily visible—such as if it is located under the house—the water will continue to drain until the homeowner gets an amazing electric or gas bill and goes searching for the reason. Also, sometimes the valve fails by opening partially and leaking a continuous small stream of hot water, like the one shown below, under an older mobile home…


This was in vicinity of laundry/bathroom. I identified the TPR discharge pipe.

From the picture, it looks to have been done after manufacture/delivery. Was there any type of water treatment or filtration that was installed?

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I had something similar yesterday at a manufactured home with a weird drain pipe near the laundry piping. I determined mine to be for condensate discharge from the air handler that was installed in an exterior closet right next to the laundry room.

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Was there a drip pan installed beneath the clothes washer? If so, this could be the drain line for it.


I’d guess a drain line from a pan since they put a screen on it to prevent insect intrusion.


Without visually verifying the origination point everything is nothing more than a guess.