Black Tank Issues

Our First Black Tank Issue

There are a few things about RVing that always stay in the back of my mind.

Not enough to keep me awake at night, but enough that I pay close attention to maintenance.

One of my biggest concerns is a tire blowout at highway speeds.

I’ve had blowouts on a pop-up camper, a boat trailer, and a three-place snowmobile trailer. Thankfully, none of them caused serious damage or injuries, but they certainly got my attention.

Another concern is having one of the slide-outs refuse to move.

Fortunately, that hasn’t happened…yet.

This morning, however, we experienced another first.

The Black Tank Wouldn’t Drain

We’ve owned our fifth wheel since 2020, and this was the first time we’d had a problem with the black tank.

During our six-month stay in Florida, we’ve settled into a routine of emptying the tanks about every five days. That seems to work well for us. The tanks aren’t completely full, but they’re getting close.

When I pulled the black tank valve, it opened normally.

Nothing happened.

No sound.

No movement.

Nothing.

At first, I wasn’t sure what had happened.

We hadn’t changed anything about our routine, so my first thought was that perhaps we hadn’t been using enough water when flushing, allowing waste to build up near the outlet.

My First Attempt

My first idea was simple.

I added more water to the tank, hoping the extra weight and pressure would push whatever was blocking the outlet through the valve.

It didn’t.

Now I had an almost full black tank that still wouldn’t drain.

Not exactly the situation you want to be in.

A Tip I Remembered

Then I remembered reading about this problem in one of the RV forums.

The suggestion was to use the gray tank to help clear the blockage.

I lifted the sewer hose a couple of feet off the ground and opened the gray tank valve long enough to let the hose fill with gray water.

I then closed the gray tank valve, lowered the hose back into the sewer connection, and waited.

The surge of gray water flowing back toward the black tank, combined with the suction created as the hose dropped, was enough to break the blockage loose.

Success.

The black tank immediately began draining normally.

Better Safe Than Sorry

Once everything was flowing again, I flushed the black tank several times to remove as much remaining debris as possible.

Hopefully, it won’t happen again anytime soon.

If it does, at least I’ll know where to start.

A Good Reminder

One of the things I enjoy most about the RV community is how willing people are to share their experiences.

You never know when a tip you read today will solve a problem months—or even years—later.

This was one of those times.

I’m certainly glad I remembered it.

Enjoy the journey.