This is the third and final part of the series, “How to Install a Toilet in a Pop-Up Camper.” The tools and materials are listed, as are the steps needed to install the toilet and/or black water tank.
Keep in mind that a black water tank isn’t mandatory. An RV toilet attached to a flange (the fitting the toilet drain hole sits on top of), can attach to a PVC pipe fitting, then to a sewer hose going directly to the RV park drain. That’s acceptable. If it weren’t, all park model RV’s would have holding tanks. Use enough water to clear the sewer hose and prevent clogs.
For additional ideas, see the notes at the end of this article.
It is assumed that the pop-up owner has measured the side wall of the box and determined there is enough height to permit a toilet installation. It is also assumed the installer has rudimentary plumbing and/or woodworking skills. Books are available at DIY stores and online with this information.
Tools Needed:
Drill with hole saw Self-tapping metal screws or metal drill bits and screws Screws- see directions to determine size Metal strapping tape PVC pipe- 3″ and 1 Ò½” diameters Cement- use all purpose cement that includes the type of plastic for the black water tank Socket set Saw and tools needed to remove or remodel cabinet space Lumber- see directions for dimensions Silicone caulk Measuring tape and markers Line chalk or spray paint Sandpaper- medium Lug screws and washers – 3/8″. Length depends on thickness of floor and wood framing Metal cutting saw, if needed (see notes about inside tank installation). Two 1 Ò½” PVC couplers- not threaded Two 2″ hose clamps
Parts Needed:
Black water tank One 3″ rubber flex fitting One 1 Ò½” rubber flex fitting One three inch elbow Black water tank valve RV toilet, closet flange and rubber foam seal (this takes the place of the wax ring used in stick-built houses) Sewer hose Black water cap Tee for water supply PEX or PVC pipe and fittings Plumbing vent cap Bayonet fitting and cap
Step One:
Select the space for the toilet installation. If a black water tank is added, make certain it won’t interfere with tires, the frame, wires, etc. Also make certain that the bottom of the tank still allows legal clearance for the roads.
The owner can choose which side of the pop-up for the installation. If choosing the “door side,” purchase enough pipe to run under the box to the drain hook-up side.
Remove the cabinet and determine if one layer of flooring exists, or two. If two, remove the top layer as needed for the space.
Measure the RV toilet’s width and length. Add four inches all the way around. The toilet usually faces toward the inside of the box. If desired, face it forward or backward, leaving enough room to get on and off comfortably.
If not installing a black water tank, go to step seven.
Step Two:
Determine where the drain hole will be. Be certain to have enough clearance from the wall for the water supply plumbing. I have an easy method for this. Place the toilet in the area, measuring enough distance from the wall for the water pipes. Take a piece of chalk or other marker and draw around the base. Pick the toilet up and turn it over.
Measure from the center of the back of the toilet to the center of the drain hole. Transfer this mark to the floor. This will be the center of the drain hole.
If using a black water tank, select a place for the vent pipe. The pipe has to go through the floor into the black water tank. Make sure the spot chosen allows this.
Using the 3″ hole saw, drill the hole for the toilet drain. Using the 1 Ò½”hole saw, drill a hole for the vent pipe.
Step Three:
Have a helper hold the black water tank in place under the trailer. Do not attach yet. Using the spray paint, coat the end of a 3″ piece of PVC pipe, and quickly place it through the hole and mark the tank. Do the same for the other hole with the appropriate size pipe. Double- sided tape will work if no helper is available.
A second method to mark the tank is to use the pilot holes. Holding the tank in place, drill the pilot holes for the hole saw all the way through the floor into the tank. Each hole is now centered.
Drill the holes in the (floor and) tank. Fill the middle space in the flexible rubber fittings with silicone caulk, and place in the tank holes. The long end of the fittings will face upward, and the short end is in the tank.
Step Four:
Cut a length of 1 Ò½” pipe, 6 inches long. Insert into rubber fitting- do not let the end touch the bottom of the tank- the pipe should be at least and inch into the tank, no more.
Place the tank against the bottom of the trailer and secure using the lug screws and washers. Make sure the screws do not penetrate through the bottom of the floor into the trailer. Place a lug screw every four inches of tank. The rubber fittings should come up through the holes slightly. This is not a problem.
Using the metal strapping, further secure the tank to the trailer by attaching the strapping to the frame using the self-tapping metal screws with washers. The strapping adds further protection for the tank. Use two to three or more straps, depending on the size of the tank.
Step Five:
Before proceeding, a word about vent pipes. In hard-sided RV’s, trailers, and stick-built houses, the pipe is solid. It runs through the roof to the drainpipe. This allows the sink, shower, and washing machine water to drain into the sewer.
In a pop-up, the roof collapses so the trailer travels in a compact box. This will not facilitate the use of a solid pipe. Rather, it will require flexible PVC pipe and hose clamps. If not available at the local DIY store, purchase it online.
Select a spot on the roof for the vent pipe. Using the 1 1/2″ hole saw, cut a hole in the roof. Keep in mind to drill in the space where the descending PVC pipe will not interfere with cabinets when the top is closed. Therefore, select a spot near or over the floor vent pipe.
Cut 2 pieces of PVC pipe, each 6″ long. Measure the thickness of the roof, and add 2″ to that measurement. Cut a third piece to match this measurement. Cement one coupler to the short piece. Cement one 6″ pipe to the other side of the coupler. Push down through the roof hole. Cement the other coupler onto the short piece inside the trailer. Cement the other 6″ pipe into the coupler.
On the roof, seal around the edge of the coupler with lap sealant appropriate for the roof type. Attach choice of vent cap onto the roof vent pipe, following the instructions for the vent cap.
The flexible hose attaches to the vent pipe in the black water tank, and to the bottom PVC hose in the roof using the hose clamps. When the roof is lowered, the pipe will bend. Lower the roof slowly, and keep the pipe from kinking while the roof is lowered. Alternatively, disconnect the hose from the roof vent and wrap around the toilet for transport. No water will come out of the hose. There may be odors from the tank, though. Venting will eliminate those by allowing the hose to remain attached to the roof pipe.
If the pipe from the roof is too tall for the desired vent cap, cut it shorter.
Step Six:
Temporarily place the toilet in position, and mark where the water supply lines need to run. Remove the toilet and run the water lines as needed.
Make sure a shut off valve is included so no one needs to run outside during an emergency.
Step Seven:
Install the closet flange in the floor, making sure the bolts are in the correct position to attach the toilet. Insert the closet bolts and twist to have them standing.
Turn the RV toilet upside down and insert the foam gasket over the drain hole.
Lower the RV toilet onto the flange, making sure the bolts are threaded through the mounting holes in the toilet.
Attach the washers and nuts and tighten to secure the toilet.
Attach the water supply line.
Cut a 3″ length of PVC pipe. Cement into the tank drain. Attach the drain valve with PVC cement, close the valve and place the bayonet cap on the opening.
Turn the water on, allow the tank to fill and give it a test. If there are no leaks, it’s good to go.
Caulk around the bottom of the toilet, and the vent pipe connection.
Notes:
Remember it is possible to install a holding tank later, if one isn’t installed initially. Remove the toilet after turning the water supply off. Cut the connector off the flange, and remove the flange from the floor. Follow the steps to mark the tank, and install the tank using a new flange. Install a vent pipe and cap as well. For an inside installation, the size of the tank is smaller, as it takes up space. Measure the height of the desired tank, and that of the toilet. Add Ò¾” for a box frame and a top board (so the person isn’t pressing down on the tank when the toilet is used), and compare the measurement to the side of the trailer box. The total height must allow the camper to close properly. A longer tank is feasible- redesign the cabinets so the tank fits under them. Cut a hole in the side of the box for the drain valve. An outside door is advisable to keep the drain valve safe during transport. Tips on video are available at http://www.rvvideosondemand.com. These videos also discuss how to install a combo shower/toilet pan, and how to install a shower. When using PVC, always sand the cut edges smooth. This is especially important for sewer pipes to prevent toilet paper and debris from becoming stuck and build up. To hide the looks of the vent pipe, paint or stain it in the same color as the background in your décor. Even though it’s in plain sight, the eye won’t register it quickly.
The toilet is installed and ready to go. For installation in a hard-sided RV, such as a home built model or vintage model, use a solid vent pipe.
Source: Mark Polk, “Mark’s RV Garage, Internet TV Show Series,” RV Videos on Demand Website, no date given
Source: The author of this article has over 40 years of experience in diverse forms of DIY, home improvement and repair, crafting, designing, and building furniture, outdoor projects and more.