Understanding Your RV Holding Tanks

Hi, I’m Bart Taylor and I’m Matt Arndt. Welcome to another First Time Camper video. Today, we will be reviewing your RV holding tanks: fresh, gray, and black.

I’ll start by showing you what your tanks look like and what the RV looks like before the floor is installed and all the connections that are made. This will help you see what’s happening under your floor.

Let’s begin with a fresh water tank. Use potable water only in the fresh water system. The fresh tank is equipped with the gravity fill hose, a supply for the water pump, and a fresh tank vent to prevent the tank from swelling when full. It also has a low point drain which allows the tank to be emptied or winterized for servicing.

Next, we will review a gray tank. A gray tank is used for kitchen sink waste water and shower water. Depending on the unit, it may have multiple gray tanks. On our example, you can see we have a gray water inlet on the top. You may have a couple inlets depending on the floor plan and you will have a vent opening at the top of the tank going to the roof of the RV. This vents the tank and removes unwanted odors as well as prevents pressure buildup and swelling of the tank. The tank will have a termination valve as seen here.

Finally, let’s review the black tank. Just like a gray tank, we have the inlet on top. However, this inlet is for the toilet. The black tank also has a vent opening going to the roof of the RV again to vent the tank and remove unwanted odors and pressure buildup. Finally, the termination valve. You may see this in several configurations, but they all do the same job.

I want to point out a couple common things. The fresh tank is designed to carry fresh water towards the pickup in the tank. The gray and black tanks are sloped to carry the waste water to the termination. This is important to know when leveling your RV. These holding tanks all have sensors and a wire harness which are connected to the monitor panel inside the RV. The monitor panel reads the level of water inside the tank and is measured in thirds. These tanks have tank heaters on them. This will vary by brand. Not all brands install these. In case you don’t know, tank heaters can be turned on to help prevent the liquid in the tanks from freezing.

Let’s move on to where the tanks are located. The tanks will be in different locations depending on your floor plan and in some cases the fresh tank may be installed above the floor, usually in a cabinet under a bed frame or as part of a pass-through storage area. You will also notice the overall shape is designed to nestle in between the frame rails of the RV below the floor. Important, all terminations are on the driver’s side of the RV, usually from the middle to the back of the RV. This is important to know for campsite preparation as it helps determine whether you have to back the RV into the site or if it’s a pull through site.

Alrighty then, let’s talk about use and maintenance. Add the proper amount of tank chemicals to your gray and black tanks before using and after dumping. Use plenty of water each time you flush the toilet. Do not be afraid to use lots of water, lots of water. I can’t stress this enough. Whether dry camping or at a campground with full hookups, you will need to use lots of water. Oh good, good deal. Use RV toilet paper as it is designed for RV use and dissolves quickly.

If you are camping and using full hookups, meaning you have an on-site dump station, do not leave the termination valves open. Leaving the termination valves open when solids are flushed allows the water to run off into the dump station and the solids will stick to the bottom of the tank and build up will occur. This can lead to problems such as clogs, faulty readings of tank levels, and bad odors. Once again, please be sure to leave the termination valves closed until the tank level warrants dumping. And remember, use lots and lots of water. Following these key points will help to avoid build up problems later.

Okay, now some maintenance tips:

Fresh tank: First, keeping the fresh water system clean and free of any potential contaminations should be a top priority. Sanitizing the system before using for the first time and annually thereafter, or whenever water remains unused for prolonged durations, is very much recommended. This will help keep the water system fresh and discourage harmful bacterial or viral growth. Maintenance of your fresh tank is a must.

Next are the gray and black tanks: maintenance on these tanks require the use of a tank deodorant and occasional cleaning. When it comes to tank deodorants, there are several on the market, just be sure to follow the label directions from the manufacturer on its proper use and amount. When you can’t dirty tank probes will cause false readings at the monitor panel. Keeping the tank probes free of debris requires proper use of deodorant chemicals, plenty of water, and the black tank flush will help this happen for you.

Hey, stop! What’s a black tank flush? Well, not all RVs have them, but a black tank flush is a nozzle on the end of the tank that a water line hooks up to to assist in flushing out the solids in the tank after the initial dump. Pretty gross, but cool huh?

Okay, plenty of water, lots of water. We recommend you read chapter 10 of the owner’s manual, where you will find helpful information and step-by-step instructions for maintaining your tanks.

Happy trails and happy tanks! We hope this helps you understand your tanks a little better and how they work and what to expect and what to look for. If you found this video helpful or have other suggestions to camp better, please leave us a comment. Be sure to like and subscribe to our YouTube channel for more RV pro tips or visit us at keystonerv.com to see all of our how-to content and thanks for watching. Of course, we are in it to win it.

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