The next stage in you RV sewage system is the holding tank. This is the tank where the sewage will be stored until it is time to dump it at the appropriate waste station. There are two different types of tanks that are used in RV’ing: portable and permanent.

RV Holding Tanks

Portable tanks are normally used for pop-ups and other smaller RV’s that do not have the room or capability of carrying a permanently installed tank. The portable tank is a mobile storage tank that is normally has built in wheels and a handle or some way to tote it around. This tank is used when the RV did not come with a permanently installed tank. Because of their mobility, they are also used in other scenarios. Say you are camping in an area that does not have a direct hook up for dumping right at your site. There may be a dump station in the campground but it is not within hose reach, or you may be boon-docking it out in your favorite spot. What do you do when your tank becomes full but you may not be ready to leave? Well, you WOULD have to: pack up, unhook power if you are using it, hitch up the truck if you have a towable, secure everything in the RV, close our awnings, close your slide-outs, and go to the dump station. After dumping, if you are not in a designated assigned spot at a paid campground, you may return to start the entire process over again in reverse and find out your perfect spot has been snatched! This is where a portable tank would be extremely beneficial. How does this sound instead? Hook up the portable tank, fill it, load it up, drive to the waste station to dump the tank and return to your untouched campsite! No packing, no hassle, and ALWAYS return to your same spot....

Portable Tanks

RV’s may also come with permanently installed waste tanks. These tanks are usually mounted underneath the RV. Permanent or portable? One is not necessarily a “better” option than the other, but they both do have their own upsides. We have already looked at some for the portable. The permanent tank however is always with you, nothing to possibly forget at home, and can be monitored using various electronic systems letting you know exactly when it’s due for a flush. Permanent tanks come in many sizes, shapes, and even have different physical drain locations. This will all vary on how your RV is set up, the space that is available, and how the plumbing is routed. A few options for tanks are: end drain, side drain, bottom drain and even recessed drain. Again the RV will determine what application is to be used. You may find it convenient to only have one option. You may even find it useful to carry both for certain cases, but rest assured whatever you decide, each tank comes is several capacity sizes to fit your needs.

Permanent Tanks

Let’s take a look at a few things that work in conjunction with your holding tanks. One useful tool to have if you live or frequent regions where temperatures reach or drop below freezing, are tank/pipe heaters. These do just what you are most likely thinking; heat your tank and pipes. The reason for this is that if you are staying in freezing conditions it is possible for your sewage and waste to freeze in the tanks and pipes. If this happens your tanks and pipes have the ability to start cracking. This will obviously also create drainage issues which lead to backups if the waste can not be removed. Most tank heaters are thermostatically controlled to turn on and off as necessary depending out outside temperatures and conditions. Pipe heaters and certain brands of tank heaters may need to be operated by the user via switches. Both are effective ways of making sure things in the tank remain in a liquid state as to not cause issues due to freezing. Most tank heaters feature adhesive backing that is used to install the heating pad on the tank/pipes. This makes it so easy that virtually anyone can install and start benefitting from the heater. Some manufactures optionally recommend using metal straps (such as the ones found on some fuel tanks) along with the adhesive to strengthen the installation of the heating pad.

Tank and Pipe Heaters

Now that we know where the sewage will be stored and we are sure that it will remain in a state that will not cause harm, let’s look at flushing and cleaning tools. Cleaning your tank is important to reduce harmful chemicals that may build up as a result of storing sewage. There are a couple of ways to clean your tanks. This ensures that you are keeping the inside of your RV odor free while also breaking down the accumulations of waste and paper that may be left after you empty the tank. The first way is with the use of a tank wand or rinse kit. This is a long wand that is placed down the toilet bowl and sprays water in the tank to dislodge any stubborn waste and odor-causing particles. Some tank rinse kits will include an adapter so that you can hook up directly to the faucet in the lavatory eliminating the need to run a water hose through the window or through the RV living space. Some rinse wands, such as the “Valterra Master Blaster,” have a “power nozzle” that is designed to raise the pressure of the water that is sprayed to help with those stubborn dry particles that may be attached in the tank. Rinsing your tank can be difficult if you have to keep the foot/hand lever pressed or having to hold the bowl valve open with your hand or other tool at the same time. There is a solution. The “Johnny Chock”, made by prime products is a simple way to keep the toilet bowl valve open while you are performing a tank rinse. When Johnny Chock is in place it will keep valve open until you remove it. This rinse method is all done from inside the RV.

Tank Wand Cleaners

Let’s take a look at what you can do from the outside of the RV if you prefer not to be performing sewage maintenance from inside the living quarters. There are two things you can do to rinse your tanks from the exterior. One is a permanent flush valve that is installed in the tank, and the other is flush kit that is attached to the dump valve before you hook up your macerator. Either way will produce very similar results, but once installed, the permanently installed valve has the advantage of spraying water directly into the tank without having to travel through any pipes or other plumbing first. Having to bend and curve through pipes before the tank is reached can reduce the pressure of the water once it reaches the inside of the tank, making the cleaning process take a bit longer. A tank rinse valve will thoroughly flush your holding tank without bringing a hose through the window. They will almost always include a built-in backflow preventer to keep sewage from contaminating your water line. All you do is hook a garden hose to the installed connection (outside RV) and flush for 2 minutes or until water from discharge hose runs clear. With a permanently installed valve, it’s that simple. If you do not want to drill an extra hole in the holding tank to install this permanent valve a “Valterra HydroFlush Tank Cleaner” will produce similar results. This is an elbow that is hooked up off of the dump valve that has a water hose connection and a anti-siphon valve. The process is similar except the hose is hooked up to the elbow instead of the valve located directly in the tank. The water travels through the dump valve and up any piping and is sprayed in the tank. The pressure may be slightly reduced as the water needs to travel before it reaches the tank. This may take a few extra seconds but it will still lead you to a clean tank, which is the end result that is wanted here!

Valve Tank Rinsers

The last and easiest way you can keep your tank clean and smelling fresh is by using drop in tank cleaner/deodorizer pouches. These pouches are simply dropped down the toilet into the tank, once in the tank they will break down 100% of the waste and paper located within. These pouches also effectively eliminate odors that can sometimes make their way back up into the RV. This is by far the easiest way to maintain a clean and odor free waste tank. Just drop one in your RV toilet and the pre-packaged portion controls odor while breaking down waste and paper. Regular use of a drop in pouch coupled with a scheduled tank rinse a couple times a season will keep your tanks thoroughly clean!


How do I know when it is time to flush my RV holding tanks? Many RV’s will come with a monitoring system that will tell you the approximate capacity level remaining in the tank. This will let you know when its getting close and you need to start preparing for a tank dump. Many RV monitoring systems consist of a bar of lights that fills to give a representation of how full the tanks are getting. This is not always the most accurate approach as there is still a bit of guess work for the user. If your RV did not come with a tank monitoring system or you would like to upgrade to one that is more accurate, Garnett Inc. makes the “SeeLevel” system. This system provides an outstanding balance between low cost and full features. Instead of single points that give you only a close approximation of how full your tanks are, this system offers a continuous level and shows an actual number, in percent of full. This is also a great system that will allow you to monitor other key areas of the RV that often require attention such as: refilling, recharging, or emptying. The SeeLevel will also monitor battery voltage, your fresh water and sewer holding tanks, and the LP Gas tank levels. With the SeeLevel kit, Garnet has created an easy way to keep track of the most important systems in your RV. If you don’t want to: get caught with no LP to run your furnace in the cold or cook meals using your gas appliances, run out of fresh water or get trapped with full waste tanks and create potential back up problems, then the Seelevel system is for you! Best of all, Tanks are monitored using Garnet’s proprietary external level sensing technology. This ends fouling problems caused by debris build-up on the holding tanks internal sensors that other systems use. This also keeps your holding tank puncture free as no holes are drilled for installation, leaving your tank with fewer places to potential leak from.

Tank Monitoring

Now we know: where the sewage is stored, how we clean it, and how we monitor it. Next we will take a look at valves, fittings, hoses and accessories. These are the necessary essentials in dumping the waste tank before the cleaning process takes place.


To Be Continued……