What a mess. We use our travel trailer at our recreational property primarily for the fridge, restroom and microwave.Well this past weekend we had our annual family picnic with about 50 people. Had the water system set for city water and hooked to my well pump. At the end of the day one of the kids runs out of the trailer and says the toilet is overflowing.Long story short, evidently the city water inlet allows incoming water to run into the gray tank, when that filled then it filled the black tank and kept pumping water up thru the toilet when it was flushed.Fortunately most of the water that dumped on the floor was fresh.This trailer was bought used for this season so no history available.Any suggestions on causes or fixes?

The city water inlet is not directly connected to the grey tank. Unless they are both using the same tank (rare), the grey and the black tanks are not connected unless you do something screwy with the drain vavles.

I'm not getting what you're saying?The gray and black tanks are two separate systems? At least on every trailer I have seen?

Looks like I'm not the only one that doesn't know what's going on? :B

Turtle n Peeps wrote:I'm not getting what you're saying?The gray and black tanks are two separate systems? At least on every trailer I have seen?As I have been told, on some designs the gray will overflow into the black tank when full. At least that can be true on some class A's. All I can say is that as soon as I shut down the well pump the overflow stopped. The tanks were pumped out the day before the picnic so were empty at the beginning of the day. I'm unclear on how the city water connection flows into the gray tank. Now that I know its happening I can hear the well pump clicking on about every 5 minutes when connected to the city water inlet.

ScottG wrote:The city water inlet is not directly connected to the grey tank. Unless they are both using the same tank (rare), the grey and the black tanks are not connected unless you do something screwy with the drain vavles.I did notice that the gray drain valve was left open by the pump truck operator. So fresh water ran out of the exterior drain cover as soon as I removed it. But the black valve was closed so I can't figure how it would have backed up thru the black valve.

Toilet Overflow | Good Sam Community

27 Replies

hawkeye-08
Explorer III
Aug 11, 2016
budwich wrote:
your likely issue is a "black water tank cleanout flush" system installed somewhere and turned on / broken valve.... OR a broken toilet valve / wand.

^^^^^ this.

This would have been my guess... but the OP reported not the case..
Tiger8r
Explorer
Aug 11, 2016
Flush the toilet then watch and see if the water quits running when you release the flush lever. If it doesn't then the seal in the valve is bad. If it does quit then my guess is wrong.
93Cobra2771
Explorer
Aug 11, 2016
Huntindog wrote:
realebill wrote:
you sure your fresh water supply isn't hooked to a black tank rinser instead of fresh water inlet ?
That diagnosis matches the symptoms exactly.

"No black tank flush on this model. I'm pretty sure now that it was a 10 lb in a 5 lb sack issue. "

OP said that a few posts up.
Huntindog
Explorer
Aug 10, 2016
realebill wrote:
you sure your fresh water supply isn't hooked to a black tank rinser instead of fresh water inlet ?
That diagnosis matches the symptoms exactly.
Walaby
Explorer II
Aug 10, 2016
I will be interested to see if a plumbing or water routing issue is identified, but I highly doubt that is it. 50 people using the various facilities, and logically at least half or more may not have a clue how to use RV toilets to me is the culprit.

Mike
TenOC
Nomad
Aug 09, 2016
I had the flush leaver on my toilet stick in the on position. The water continue to run into the toilet. I was not connected to city warter -- on the pump and hear the pump to continue to run after using the toilet.

Shut the pump off, a little grease on the flush leaver and a cut-off value on the toilet inlet.
3oaks
Explorer
Aug 09, 2016
Being it was a used trailer, who knows what, if any alterations, to the plumbing system the original owner made?

Naturally without hands on investigating, everyone is offering their best guesses as to what the problem really is. It really shouldn't be that hard to figure out through the process of elimination. :@
sundance_8
Explorer
Aug 09, 2016
rekoj71 wrote:
beemerphile1 wrote:
Are you certain the water connection was the potable connection and not the black tank flush?

This is what I'm wondering. In 96 I'm not sure if the tank flushers were standard like they are on some RV's now, but one could have been added.

Are you sure that your hose is connected to the city water inlet and not to a black tank flush. If the black tank flush is left on too long and the black tank handle closed the black tank is filling up. It's a common practice when someone wants to get the tank really clean, but it can backfire if they forget and overfill the tank and then the mess happens just like you describe.

You may have still had water pressure at the sinks if you had water in your fresh tank and were running the RV's water pump.

No black tank flush on this model. I'm pretty sure now that it was a 10 lb in a 5 lb sack issue.:S
rekoj71
Explorer
Aug 09, 2016
beemerphile1 wrote:
Are you certain the water connection was the potable connection and not the black tank flush?

This is what I'm wondering. In 96 I'm not sure if the tank flushers were standard like they are on some RV's now, but one could have been added.

Are you sure that your hose is connected to the city water inlet and not to a black tank flush. If the black tank flush is left on too long and the black tank handle closed the black tank is filling up. It's a common practice when someone wants to get the tank really clean, but it can backfire if they forget and overfill the tank and then the mess happens just like you describe.

You may have still had water pressure at the sinks if you had water in your fresh tank and were running the RV's water pump.
icanon
Explorer
Aug 09, 2016
93Cobra2771 wrote:
I'm betting black water got filled up. Last person using it filled it so full that the toilet valve hung open because of blockage. That is why your water quit overflowing when the water supply was cut off.

X2