How to Install an RV Holding Tank

Lead Image
  • 3-6 hours
  • Advanced
  • 100-500
What You'll Need
Pen and paper
Holding tank(s)
Water pump

There are three types of tanks that can be installed as a holding tank for an RV. The first type of tank allows you to hold fresh water to drink, shower, do the dishes, or flush your toilet. The second type of tank, called a “gray-water tank,” holds wastewater from all drains, except for toilets. And, the last type of tank, or a “black-water holding tank,” holds liquid and solid waste from the toilet. No matter what type of tank you want to install, you can complete your RV project with the guide below.

Step 1 – Choose Your Holding-Tank Material

Holding tanks are made from different types of materials. They can be made from plastic, polyethylene, and acrylonitrile-butadiene-styrene, or ABS. Decide which material best suites your budget and application.

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 specific in your drawings, making sure you mark 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. For a black holding tank, you will want your toilet to be positioned over top of it. A gray tank should be between the shower and sink. A fresh-water tank should be centrally located to make hooking it up to the shower, sinks, and toilet an easy job.

Step 4 – Mount the Fresh-Water Pump

Follow the directions provided on the water pump to properly install it. Generally, you will need to mount the pump between your fresh-water plumbing and fresh-water tank. Mounting it here 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 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 tank. The size of this tank should reflect your individual travel needs. For example, how far will you travel between camps without facilities to empty the tanks? In addition, Make sure your holding tank has fittings in an easy-to-reach area. Most manufacturers will mount the fittings to your specifications.

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

Step 6 – Maintain Your Tanks

Check on your tanks often to ensure they are working properly. Older tanks can become loose, damaged, or cracked. However, repairing these tanks is an easy project to complete, too.