How to Install an RV Holding Tank

To put it simply, there are three types of tanks that can be installed as a holding tank for your RV. The first type of holding tank will allow you to hold the fresh water. This is water you can use to drink, shower, do dishes, and flush your toilet. The second type of holding tank is called a gray water holding tank and is used to hold the waste water from all the drains, except the toilet. The last type of holding tank is called a black water holding tank, for the liquid and solid waste from the toilet similar to that of a septic tank. If you are looking to install a holding tank in your RV, here is how you accomplish the task.

Step 1 - Choose Holding Tank Material

Holding tanks are made from different types of material. They can be made from plastic, polyethylene or ABS. First, decide which of the materials is best suited for your application and for your personal RV experience.

Step 2 - Draw out Your RV Design

Sketch the outline of your RV and decide where the best location is for your holding tank. Keep in mind where the plumbing fixtures are located on your RV. You will want to be very specific in your drawings, marking where the toilet, sinks and shower fixtures are located.

Step 3 - Draw in the Holding Tanks

Next, outline where the holding tanks are to be installed. You will want to place the holding tank in such a way that your toilet is positioned right over the black holding tank. This will make sure that your toilet will empty into the black tank in a straight run, without bends or curves. The gray tank should be some where between the shower and sink, and the fresh water holding tank needs to be centrally located to make hooking up to the shower, sinks, and toilet easy.

Step 4 - Mount the Water Pump

Follow the directions on the water pump on how to properly install it. You need to mount the pump between your fresh water plumbing and fresh water tank. This will help to pressurize the fresh water that will be delivered to the faucets, shower, and toilet. Pay attention to the manufacturer's instructions relative to the type of wiring needed during this portion of the installation. You will need to install the exact type and size (gauge) of wire for your specific water pump.

Step 5 - Mount the Black and Gray Holding Tanks

The black holding tank is the most important holding tank. Purchase the holding tank that meets your RV specifications and measurement allotments. The size of the tank should reflect your individual travel needs (for example, how far will you travel between camp grounds without facilities to empty the holding tanks (black and gray). Make sure your holding tank has fittings in an easy to reach area. Most manufacturer's will mount the fittings to your specifications.  While you are planning where you can place the tanks keep in mind the need for the plumbing pipe locations on the tanks themselves, remembering to include on your plan the location of drain valves on the tanks for easy access when you need to empty them. Holding tank manufacturers will place fittings on the holding tanks, anywhere that you specify.

Mount the tanks based on the manufacturer's directions. If you are installing a large set of tanks, you will want to purchase additional support bars or straps for extra security measures.