Washer drain spewed, then exploded

[Akagis_white_comet]

So after replumbing the whole house's supply side and doing a one-gallon test on the washer drain (to test for backing-up leaks at the opposite end of the house), I gave my fiancee the green light to use the washer.

We fire it up with a load of laundry, then go outside to do some yardwork. I come back in and the bathroom (where it is) is flooded from the rinse cycle. After killing the washer and shutting off the supply valves, we mop it all up and I give it another go. Washer drains fine now. No flood, but I hear it dripping underneath. Pop the underside skirting off and it's a constant stream of water coming from the washer drain piping.

It is a mobile home and there was circumstantial evidence of prior occupants dumping used cat litter down what I suspect is any and every possible drain (even the kitchen sink!!!). My understanding is that cat litter is a HUGE no-no as it basically turns to cement inside pipework, so I am a bit confused about how such actions could result in the washer drain busting open like this. Could someone please walk me through this?

 

[Kreemoweet]

It's entirely unclear as to exactly what is leaking, and where. You say it leaks from "washer drain piping" underneath the washer.
Normally, there is only a flexible drain hose (typically made of rubber) under a washer, and not any sort of "piping", which refers
to the rigid, permanently installed plastic or metal pipes. A leak there would indicate an unsecured or deteriorated hose. And what
does "exploded" mean? Plumbing pipes simply do not "explode", although they sometimes leak.

 

[Sponsor]

 

[Akagis_white_comet]

It's entirely unclear as to exactly what is leaking, and where. You say it leaks from "washer drain piping" underneath the washer.
Normally, there is only a flexible drain hose (typically made of rubber) under a washer, and not any sort of "piping", which refers
to the rigid, permanently installed plastic or metal pipes. A leak there would indicate an unsecured or deteriorated hose. And what
does "exploded" mean? Plumbing pipes simply do not "explode", although they sometimes leak.

The drain hose is fine, no issues there. Where it links into the house plumbing (the standpipe) is okay too. There is a trap at floor level, it works fine. Where it goes BELOW that is where things went bad. First, it flooded the room. Mopped it up, then tried again and something below floor level in the drain pipes blew open.

 

[Michael Young]

take a long piece of metal (all thread works well). Shove it down right next to where the drainline penetrates the floor. Shove it down until you hit the protective layer underneath the trailer. someone underneath will be able to see. CUT the under-layer so you can pull back the insulation and see what's going on. Once you can see it and get us a picture, I'm sure there are quite a few guys here who can tell you how to make the fix

 

[Cacher_Chick]

One thing to note is that a washer drain hose should never be ridgidly connected to the standpipe. It must have an air gap which would have prevented the drain line from becoming pressurized if there were a blockage.