The reason for these posts are to help others so they don’t do what we do OR what we’ve seen other RVers do. OR… if you are new to RVing you can learn from our mistakes because there is so much to learn. One thing people constantly wonder about is whether they can leave their black tanks open. Today we’ll take a look at how you should handle your black tanks. So let’s get started.
Do you leave your black tank valve open or closed? A black tank holds any water that has passed through a toilet. This includes human waste that you need to dispose of in a sanitary manner.
Many RV parks have full hook-up sites. Keeping your RV connected to the sewer drain and being able to empty your tanks quickly, can save you a lot of time. RVers love full hook-ups because of the convenience. You won’t have to worry about dumping your tanks into a portable tote or finding a dump station. You can quickly and easily empty your tanks without having to pack up your entire site each time. However the convenient full hook-ups may make people wonder about leaving their tanks open. Let’s see why you should keep them closed.
Black Tanks on Full Hook-Ups: Leave Closed
It’s a common mistake many RVers make to leave their black tanks open when using full hook-ups. Leaving your black tanks open allows any liquids that enter your tank to drain out immediately. This becomes a problem as any solids in the tank get left behind.
A “poo pyramid” can form in a tank as the solids gather over time. It doesn’t take long for these solids to combine creating a mass that’s too large to pass through the valve for dumping. This will clog your tanks and cause a frustrating and disgusting situation.
You can reduce your chances of a “poo pyramid” by keeping your black tank closed and using a lot of water with each flush. This will help solids break down while they’re in the tank. When you empty the tank later, the force from the water rushing out will wash out the solids as well.
So how long does it take to fill your black tank? The amount of time it takes for you to fill up your black tank varies from one RV to the next and one camping style to the next. Black tanks come in a range of sizes, typically from 20 to 60 gallons. Check the owner’s manual for your RV if you aren’t sure what size tanks you have. Another factor to consider is how many people will be using the restroom in your RV.
Just for reference, when your toilet ‘burps’ or bubbles when flushed, you know its time to dump your black tank. A clog or your tank is full is creating negative air pressure, Instead of air flowing through the lines, the air pushes back and causes the gurgling sound. Sometimes, you’ll also see the toilet water bubble. This is probably the most accurate way to determine when you need to dump your tank because you can’t always count on tank sensors.
Tip: Keep the black tank valve closed until the tank is at least 2/3 full. (Dumping the tank when it is less than 2/3 full will not allow the tank to empty properly). Always drain your black tank first. After dumping its a good time to rinse the tank with the sprayer wand or run a lot of water through while the valve is open.