RV Waterless Waste Valve & Shower Drain Install

December 17, 2020

The Problem

When we first moved into our camper, we immediately noticed a problem. We were getting a terrible septic smell coming up into the camper every time we ran the bathroom vent fan. At first I thought the valve in the toilet was bad, but after some sniffing around it was pretty easy to determine that the smell was coming from the shower. I didn’t immediately understand how we could be having this problem. I assumed that the p-trap under the shower was the same as the one under the sink, just a standard residential p-trap. To test this, I ran some water in the shower and turned on the fan again. We still had the terrible smell. Next I went into the basement of our camper to see what the plumbing actually looked like. That’s when I noticed there wasn’t a standard p-trap, but some sort of one way valve under the shower. I did a little googling and found that what we actually had was a Wavin BV1B/UB HepvO Sanitary Waste Valve.

The Valve Installation

I started by removing the air vent in the wall of the bunkhouse to gain access to the plumbing under the shower. From this location I was able to reach the existing one way valve. I started by laying down a towel to catch any water or debris from the valve. Then I loosened the fittings, removed the valve and could immediately see what the problem was. The rubber seal inside the valve had been damaged, and was turned completely inside out. It was allowing gasses from the RV park’s septic system to come back up into our camper.

I removed the new valve from the packaging and installed it in the same direction as the old valve. If you look closely at the valve you will see a directional arrow. Make sure that the flow of the water follows that arrow, from the shower to the grey tank. The valve should also be installed with the ribs pointing down. I first installed the valve with no teflon tape or sealant of any kind and tested it by running the shower for a few minutes. I found that I had a pretty good leak on one side. I applied some teflon tape to the threads of the valve, and found that it was much easier to get a good seal this way. After I got the valve installed and had a good seal on both sides, I noticed that I had a very slow leak from around the shower drain.

The Drain Installation

I was a little frustrated at this point after laying on my back, crammed into an air vent, wedged between our furnace and AC ducts. So I did what any self respecting man would do, I called it a day. I left a towel down to catch any water that might leak and left the air vent open to check it after any showers were taken. I then ordered a new shower drain and some plumber’s putty.

After the new items arrived I got back after it. This time I decided to go in from the basement side near the plumbing control panel. I was able to reach the shower drain more easily from this location. I started by disconnecting the 90º elbow from the bottom of the drain. I was able to keep the drain from spinning by wedging a pair of needle nose pliers up inside it. Then I used a pair of channel lock pliers to remove the nut that sandwiches the drain to the tub floor. I then pushed the drain up into the shower basin.

I moved up into the bathroom to install the new drain inside the shower. I started by cleaning around the drain hole in the shower basin. I completely removed all the old putty that was around the drain hole, and used some bathroom cleaner to make sure it was good and clean. I then scooped out some plumber’s putty and rolled it in my hands to create a long cylinder. I placed this around the hole in the shower basin and pushed the new drain down into it. I was able to work the drain down into place and remove some extra putty as I was going.

Back underneath the shower, I then added the washer and the nut to hold the drain in place. I used the same process with my pliers that I used when removing the old one. I wedged the needle nose pliers into the drain to hold is still as I tightened the nut with the channel locks. I then reconnected the 90º elbow going into the rest of our plumbing. After a quick test, I could see that we were smell and leak free!

Results

This was supposed to be a simple project of just changing out a waterless waste valve, but it ended up being a little more intensive. I’m glad that I really looked into all of the issues and was able to discover the slow leak in the shower drain as well. Who knows how long that part had been leaking. With us living full time in our camper and taking many showers this could have created a much larger problem in a short amount of time. Overall, it was not a hard project. The worst part was fitting under the shower to work on it.