Tuesday, October 19, 2021


Black tank horror story averted: Our RV almost flooded!

By Nanci Dixon
At about two in the morning my husband gets up to use the bathroom and steps into a flood plain. After catching himself from slipping on the wet tile floor, he turns on the light and sees an abundance of water running past the door. Unfortunately, he wakes me up, too.

It has been pouring outside nonstop for six hours and our first thought was that the vent was open or it was coming in the air conditioner vents. Nope.

Then, I notice that the black water tank was at 100%. It has never been at 100%! I took a flashlight and looked down “the hole.” Yup, I can see water edging up the pipe and it is cleaner than normal.

My husband immediately runs out in the pouring rain to dump the tank. Is a vent cap off on top of the motorhome and filling the holding tanks in this torrential downpour? Worse yet, is that black water seeping across the floor, into the kitchen and down the hall? Nope, survived the sniff test and the water is clear.

Valve leak was the culprit

We start looking for leaking pipes under the sinks. Nope. We finally pulled the shroud from around the toilet to find a valve was leaking and seeping under the toilet, filling the black water tank.

Husband runs out, again in the pouring rain, and turns off the outside water faucet and I turn off the water pump. Major disaster averted. Back to bed. The rain has escalated to drumming on the roof and thunder has started pounding. Now I needed earplugs.

Added to our “To Do” list is to tighten the screws on the toilet valve after jostling around for more than 2,000 miles on notorious I-10 and I-70. The roads to Sequoia National Park and Yosemite National Park were not smooth sailing either. It is, after all, a house on wheels, and every other screw seems to shake loose.

After tightening the screws on the toilet, stopping the flow, my husband went out to turn the outside water faucet on while I watched diligently for leaks. He noticed that the water pressure gauge was nearing 65 PSI. The pressure gauge had failed and was contributing to the problem. We carry an extra gauge just in case – and at that moment, I was sure glad we had it.

We have always heeded the warnings of other RVers and turned off the water at the outside faucet whenever going somewhere overnight. But we have never felt the need to do so when leaving for a short time. Since we have been RVing for more than 25 years and this is our first inside flood, I doubt we will start turning the water off at night. But we will certainly start turning it off when gone for longer than an hour or so.


Fixing a leaky toilet valve seal



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5 months ago

I’ve had a somewhat similar problem in that the waste pipes under the sinks come loose. I know check them after every trip. Otherwise a sink full of dishwater may dump into the cabinet

Part of the problem is a poor install under the kitchen sink. The pipe from the sink drain was cut too short and the trap was lifted to fit–putting tension on the joint.

Uncle Swags
5 months ago

Two of my favorite RV games – What was that noise? and Wonder where this screw goes?

I fill my water tank and turn off the water pressure at source.

My new game is now What Next????

5 months ago

My new neighbor just had that same problem with the 2018 5th wheel she just moved into. I had not heard of it but now see how common it can be.

5 months ago

We were in a state park in Mississippi when we woke up one night with water running out of the toilet onto the floor. After doing some checking we figured out the water pressure in the park was only about 10 psi. We had flushed the toilet in the night and there wasn’t enough water pressure to kick the valve off on the toilet. So the water just ran and ran. Our solution was to only fill the tank and use the pump. And at night we turn off the water pump. No problems since then.😁

5 months ago

Never had a problem like this but I always turn the water off (inline valve at trailer connector) when we leave, even for a short walk around the RV park.

5 months ago
Reply to  Doug

We do the same thing, we never leave without turning the water off. Don’t ask why we started doing this.

Robert N. Cordy
5 months ago

We too have experienced surprise interior water leaks. Thus we only use water from our tank and never connect to “city water”, except to refill the tank. Should a leak develop the cycling water pump alerts us.

Bob Staples
5 months ago

I’ve heard of this happening more than once and then it actually happened to our friends who joined us for their first RV trip in a rented motorhome. I like Larry’s suggestion, so I am going to buy a water alarm to keep on the bathroom floor, just in case.

PS: It would great to know the brand of your toilet. I think our friend’s rented motorhome had a Dometic toilet.

5 months ago

I’ve installed water sensors in every location, around the toilet, under the shower and sink, next to the water heater, for an early warning of a leak. They’re connected to a hub and via wifi connection to an app on my iPhone. Offers some sense of comfort.

Diane Mc
5 months ago
Reply to  Larry

Can you share what product you used?