Hello all,Today at our seasonal site, my wife arrived several hours before me and turned things on as we usually do. When we leave for the weekend, we turn the water off and release the pressure in the lines, etc. So today she arrives, turns on the water, hot water heater, etc. She isn't getting water, so she goes outside and is checking things. Our neighbor, trying to be helpful, comes over and finds a valve junction I put on for various water lines (fresh water, black tank flush, hose, etc.). He turns on the black tank flush and tells her he found the issue and try it. She goes in, water works (because she just had to wait a moment for the fresh water pressure to build).About 45 mins later, she hears a loud bang, and water is coming out underneath. She calls me and describes what happened. After asking a few questions, I realize the black tank flush built up pressure, ruptured something and is spilling out. She dumped the black tank, turned off the black tank flush and had someone at the campground confirm things... That's what happened. So, we need some repairs I'm sure. I plan to have a professional deal with this. I don't know if the tank ruptured or just blew a fitting, but while I'm handy, I want this done right. My question is this... It's probably going to be a few days before we get someone out to look at it and fix it. I know there's black water in the area between the floor and the underbelly plastic seal. Should I wait for a pro, or do I need to get this open and drained asap? I don't want mold or worse, but I don't want to damage anything salvageable (like the plastic underbelly cover) if the pro would handle this differently.Thoughts? Stupid error. Neighbors are nice enough, but I wish they minded their own business. Looking for adviceThanks, - Mike

Not good...who needs this kind of grief...But, I know how I am. I would probably start (carefully) getting into it. Get it opened up, cleaned out, starting on drying and poking into what needs to be fixed....This will save you money and more grief.As far as your statement, "Neighbors are nice enough, but I wish they minded their own business.".....I'll just say hold my tongue and say nothing...Good luck with it...this kind of thing happens. It's all part of the adventure.

I don't see how any of this could happen?The tank is a vented system. No pressure to build up.The lines are all pressure rated and can all dead head with no problems.You can have water pour out of the vent on the roof when the sprayer is left on but that didn't happen. Something is not right here?

Maybe it just blew the hose off of the fitting where it connects to the flush valve at the tank. I had that happen before.

Well, I wasn't thee, so I'm going by what I was told. Perhaps it was just a valve or fitting, but something broke from the black tank flush and there's a leak underneath. Nothing inside the RV, though.So, carefully pull the unberbelly cover and start looking?

I agree with Turtle - kinda doubt you can rupture a tank by running water into it. Chances are a fitting popped loose or maybe a strap holding up the tank busted. If it were me I would at least do enough work to determine what actually happened and then make a decision on whether you want a "pro" to fix. From what I have read the "pros" can charge a hefty premium when working on black water issues.

Black Tank Leak From Over Pressure | Good Sam Community

GrandpaKip
Explorer II
Jun 11, 2018
If your floor bottom is covered by Darco, probably no damage to to whatever the floor material is made of. Even if not covered, as long as it is wet or damp for just a few days, not weeks, it still should be fine. Also, if the insulation is totally soaked, it is probably not even contacting the floor any more.
If you have to wait for someone else to drop the tank, I would fashion some type of rake to remove what insulation as you can and put a couple of fans under to start the drying process.
Here’s hoping it all ends well.
Huntindog
Explorer
Jun 11, 2018
Get that insulation out NOW!!

It is like a wet sponge soaking your subfloor.

This can destroy it in short order... And for all practical purposes, destroy the unit.
Get it out and put some fans on it. Time is of the essence. It may already be too late.
datadr
Explorer
Jun 11, 2018
I pulled the underbelly down today on the back half. It was messy and wet and was able to see what happened. The black tank did in fact rupture at the top flange seal across the entire top front of the tank. I wasnt able to get pictures, but it's definitely that. The force of the rupture separated the bracket on one side and the tank is dislodged.

I'll need to pull the other half of the underbelly down as there was a little more effluent on the front part from wicking. There is also some in the floor insulation above the tank from the force of the rushing water out of the tank. There was a small gap in vapor barrier right there, so that will need to come out.

The only good thing from this is that the black tank was emptied before we left the last time we were there, so the only thing really in there was remnants in the bottom of the tank, a few dissolved tank tabs, and fresh water. The smell wasnt that bad overall, considering what happened.

Have someone coming to asses things and see about next steps. A for the neighbor, I have no intention of calling it out and such. They are good people and meant well. I certainly won't thank them for this, as suggested, but they didn't mean harm, and I'm not the kind to want others to be accountable when I should have never had the black tank flush even hooked up without clearly labeling it as such.

Should I be getting that floor insulation out now? I may need to drop the tank out to get to it, which I'm not sure I'm qualified to handle.
turbojimmy
Explorer
Jun 10, 2018
bartlettj wrote:
You're lucky it wasn't your toilet base gasket.

That's what I was thinking. On my rig that would be the first point of failure once the black tank was overfilled (don't ask me how I know).
bartlettj
Explorer
Jun 10, 2018
I would expect 45 minutes worth of water flowing into the black tank would have resulted in water coming out the top vent. However, even if that's true, 10 feet of water is more pressure than your tank would normally see so something could have let loose just from that. You're lucky it wasn't your toilet base gasket.

Good luck, let us know what you find. At least the water was probably mostly clean.
Turtle_n_Peeps
Explorer
Jun 10, 2018
datadr wrote:
Well, I wasn't thee, so I'm going by what I was told. Perhaps it was just a valve or fitting, but something broke from the black tank flush and there's a leak underneath. Nothing inside the RV, though.

So, carefully pull the unberbelly cover and start looking?

My point is this. Your neighbor didn't do anything wrong or I should say did not or could not have caused the problem.

The title of your thread is "black tank leak from over pressure." Then you went on to say that your neighbor caused this mess and you wish he would have minded his own business.

If in fact the black tank split (I'm 99% sure this did not happen; but lets say it did) you should be thanking the guy because the failure happened in the campground and not traveling down the road. Tanks are vented and if yours was not venting for some reason your neighbor did not cause the problem.

If in fact the sprayer caused the problem; (fitting blew off or something like that) it was a mechanical failure and your neighbor again had nothing to do with that, or I should say did not do anything which could cause the failure. It would have happen to you the next time you used the sprayer system.

As far as pulling the belly; sure. It's the only way to see what is going on and exactly where and what the point of failure is. This whole deal sounds more like a fresh water piping failure to me. Like was said, maybe a fitting blew off or something like that. If that's the case, it should be an easy(er) fix because working on a fresh water system is a LOT more fun than working on a black water system.

In any event I hope and wish your problem is an easy fix because working on a trailer in a campground is not any fun no matter what the problem is.
westend
Explorer
Jun 10, 2018
Most likely suspect--backflow preventer on tank flush water supply. They are made notoriously cheap.
badsix
Explorer
Jun 10, 2018
HOPEFULLY it was clean.
Jay D.
ksg5000
Explorer
Jun 10, 2018
I agree with Turtle - kinda doubt you can rupture a tank by running water into it. Chances are a fitting popped loose or maybe a strap holding up the tank busted. If it were me I would at least do enough work to determine what actually happened and then make a decision on whether you want a "pro" to fix. From what I have read the "pros" can charge a hefty premium when working on black water issues.
datadr
Explorer
Jun 10, 2018
Well, I wasn't thee, so I'm going by what I was told. Perhaps it was just a valve or fitting, but something broke from the black tank flush and there's a leak underneath. Nothing inside the RV, though.

So, carefully pull the unberbelly cover and start looking?

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