Bring up this question online and you’ll get lots of different opinions. Why does it really matter?

Well, it matters because you want a lot of liquid in your tank before dumping to help flush all the solids out. If you dump your black tank on a daily basis, or worse, just leave the black tank valve open, you’ll get the dreaded poop pyramid. All the liquids will drain out and leave the solids. The goal here is to make sure your black tank is over half full before dumping, which takes us back to the original question – when is it really full?

Tank sensors are inaccurate, at least after the first couple of uses. Some people use a set number of days. That might work – after you’ve figured it out some other way but tanks are different sizes and the way people use their toilets is infinitely variable. Some folks just get a feel for it, but verify by shining a flashlight down the toilet pipe. I guess that works but, ewwwww!

I personally wait until my toilet burps back at me. What????? Yes, when you flush your toilet and the tank is full enough to start covering the vent pipe, it will burp at you. You want to pay attention to this when it first starts burping. You really don’t want that to happen after taco Tuesday, if you get my drift. Some folks just can’t visualize a burping toilet so I made a video of it for your viewing pleasure. Feel free to rewind or use slo-mo.

After the last few posts, I realized that I need a category for RV maintenance. It seems to be taking up more and more of my time now that the 5th wheel is 5 years old.

After the wet bolt kit upgrade, the next project was (drum roll please) the toilet. It’s actually been an ongoing project for the last few months. For you non-RVers, our toilets are much different. There is no toilet tank holding several gallons of water to push stuff through the pipe. We basically have a 2 piece toilet – the bowl and the base. Between those 2 pieces is a flush valve to allow ‘stuff’ from the bowl to enter a pipe, which leads straight to a holding tank. We flush with a foot pedal. Besides opening the flush valve, it also sprays water into the toilet bowl. When you release the pedal it closes the flush valve and a small amount of fresh water remains in the bottom of the bowl. That small amount of standing water provides a barrier so that odors from the holding tank don’t come back up into the bathroom.

It’s fairly common for RV toilets to develop leaks around that flush valve so the bowl will no longer hold water. I’ve experienced this problem in the past and there are various solutions depending on the cause. Sometimes that opening just needs a thorough cleaning. Someone actually makes a special tool for it. I just use a circular toilet bowl brush. Sometimes a few ounces of vegetable oil in the bowl will recondition the rubber seal and make everything great again. And sometimes you just need to replace the seal. Not a fun job, but also fairly easy.

During my latest problem I tried the cleaning. That fixed the problem for a few days. I tried the vegetable oil. That lasted about a week. I changed the seal. That lasted about 3 weeks. So I started looking at other parts that could be changed. I changed a drive arm and the flush valve itself. Hell, I even tried some FlexSeal paint on the bottom of the bowl. Still no better. I’d been checking YouTube videos for other ideas and looking for more options in online forums. All the forum responses were ‘Buy a new toilet’. I found one YouTube video where the guy did a very good job of documenting 2 parts replacements. At the end of that video, he fessed up that given the same circumstances in the future, he would just buy a new base. That’s all I needed to hear at that point.

I checked online prices and shipping times, then found a local RV dealer that had one in stock for a reasonable price. That afternoon I installed the new base in under an hour (practice makes perfect). And it just felt different when I tested the flush. More solid. I didn’t mention it earlier but this particular toilet has a porcelain bowl but a plastic base. I’m not sure if the plastic got compressed enough to allow the leak or if an O ring just deteriorated. That O ring didn’t show up on any of the parts lists for the toilet but there was a definite difference between old and new. Just in case, I measured it and ordered a few spares for future use. So far so good on water staying in the bowl.