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As part of restroom trailer maintenance, it is important to understand how to winterize a restroom trailer.  If you plan to store a restroom trailer in freezing temperatures, you should consider winterizing it to prevent damage to the plumbing system and components. Obviously, freezing damage can harm any component of the system, including the water tanks, toilets, urinals, pumps, or restroom trailer piping.

Before beginning to prepare the restroom trailer for cold weather storage, a brief explanation of the plumbing system can help you to understand the operation of the restroom trailer.  Which is part of the restroom trailer maintenance.


The plumbing can be divided into two separate systems. Firstly, the freshwater system consists of those items used to deliver water for your use. While the wastewater system includes the drains and tanks storing and removing water already used in the restroom trailer. Both systems and components require some “winterization”.

If your new restroom trailer was built with an on-board fresh water holding tank, then the plumbing system has the dual ability to contain water with on-board storage. Or use facilities provided by an external pressurized source. In either case, the components of the restroom trailer plumbing system operate like those in your home. Components of the plumbing system consist of strong, lightweight, corrosion resistant materials. Importantly, the materials provide long life and easy cleaning. By following the instructions outlined here, you can expect efficient operation with a minimum restroom trailer maintenance.

(It is important to note, that if your restroom trailer was manufactured during the fall or winter months the factory has anti- freeze placed in the water lines.  Which protects them from freezing. You can recognize the anti-freeze liquid by its pink color. This anti-freeze should be flushed from the system after trailer finishes heating. And before each time the trailer gets placed into service).  Never assume your trailer has been winterized.  Always confirm before storing your trailer in freezing weather.


The winterization of the restroom trailer can be accomplished by “adding anti-freeze to the plumbing system” OR by “draining and blowing the water out of the system”.


Removing the water heater and replacing the freshwater system with an RV trailer brand anti-freeze is the first common method to winterize a restroom trailer. (This is available at any large retailer or RV dealer).  Level the restroom trailer to help system drainage. Confirm you have a proper electrical source to the trailer.


Begin this process by first draining as much water out of the on-board fresh tank and water lines as possible. The freshwater tank will have a drain located on the bottom of the tank.  Therefore, the water will drain into the waste holding tank below the floor. Or if allowed, drain to the ground outside.

1. If your restroom trailer has a water heater, first turn off electric to the water heater so you don’t burn up the heating element in the empty water heater.

2. Turn the water pump switch on.

3. Open all faucets. (Can begin with faucet or toilet farthest from water supply)

4. Run water until all water empties from the freshwater tank and water lines. This water will be drained into your restroom trailer wastewater tank.

5. Drain the wastewater tank to remove as much water and waste from the restroom trailer as possible.

6. If the water heater has a drain, firstly open and drain out water. Secondly, close the water supply valve and open the bypass valve to allow antifreeze to flow bypass the water heater. If it has no drain (which is common with small water heaters) the water heater will need to be removed or filled with antifreeze.


We recommend an RV anti-freeze (propylene glycol) for your restroom trailer maintenance. To add anti-freeze to the restroom trailer plumbing system it can be drawn from the existing on-board water tank. Which you can accomplish by dumping anti-freeze directly in the tank. Or, by drawing from an individual container. It will take several gallons to be added to the system. Alternative choices than the traditional anti-freeze can be found on the internet.

1. After you dump anti-freeze into the restroom trailer fresh tank, turn on the water pump and open all of the fixtures until the pink anti-freeze flows out. (Can begin with faucet or toilet farthest from water supply)

2. Close each faucet as the pink solution flows freely from it. This also includes the water line to the toilet.

3. Perform this process with every restroom trailer sink and toilet.

4. Confirm anti-freeze is in every p-traps for the toilets, flushing urinals (if applicable) and sinks. An amount of anti-freeze left in waste tank will prevent the restroom trailer waste tank from freezing.


To use the compressed air method to winterize the restroom trailer, begin with the steps above to drain the existing water out of the system.

1. In order to clear the freshwater lines with air you will need an air compressor and a fitting to attach to the freshwater lines. Connect the air hose to the city fill connection.

2. If the restroom trailer has an on-board freshwater tank, open the fresh tank fill valve and let the compressed air clear the fresh tank supply line. Once the water has cleared this line, close the valve.

3. Open the city fill valve. Then go to each of the sinks, toilets and urinals and let them run until only dry air comes out.  It helps to begin with the fixture farthest from the air supply. Normally, it takes several tries of opening the restroom trailer toilets and sinks until only air comes out and water has been removed.

Even though the water may have been removed from the freshwater system, you will still need to add anti-freeze to any P-traps where water may be trapped in the wastewater system. This includes sinks, toilets or urinals.

Be sure to read the literature supplied with restroom trailer plumbing components, such as the pump, for troubleshooting tips.  Also, remember electrical problems possibly cause water system problems. A variety of reasons can cause lack of power to the pump. If you do not know how to locate and/or repair a plumbing problem, a qualified plumber should handle the job.


Before using the system again in warmer weather, completely flush the restroom trailer systems with water, flush the toilet, and sanitize the entire freshwater system. In the event, when using the restroom trailer during cold weather, the water in a tank or drain line should happen to freeze, you should take immediate steps to thaw it before damage to the system occurs. DO NOT con­tinue to use water system components if such a condition exists. If damage has occurred, make sure to have it repaired before using again.


As described, the waterless urinal is just that,” waterless”. It does not have a freshwater plumbing line connected or a flush valve installed. The urinals don’t flush, but instead, they drain by gravity into the waste tank of the restroom trailer.

Importantly, the key to the waterless urinal is the special cartridge trap at the bottom of the urinal.

Because the urinal cartridge does collect uric sediment, we recommend you replace the cartridge consistently. Change the waterless urinal in the restroom trailer every three months or about 7,000 uses. After you pull the old cartridge trap pulled and before you place the new cartridge trap in the urinal, we recommend cleaning the restroom trailer urinal piping. Clean by pouring gallons of water into the urinal and down the drain into the restroom trailer holding tank.  Then, you can easily change the cartridges with a tool provided with the cartridge. At the present time, the internet has many tools readily available.

Restroom Trailer Maintenance and Cleaning of “Waterless Urinal” in a Restroom Trailer:

Perform cleaning once a day, or as needed.

Remove any litter in the bowl and clear cartridge holes.

Use mild disinfectant cleaner on a cloth to wipe the bowl.

DO NOT use aggressive/concentrated detergents or any other chemicals on your restroom trailer.

DO NOT dispose of water into the restroom trailer urinal.


Add water to bowl

To add water to the restroom trailer toilet, press the flush pedal part way down. Water flows into the bowl while flush ball remains closed.  If the flush ball moves, let up on the pedal slightly. Adding water to an empty restroom trailer toilet bowl helps prevent holding tank odors from entering the living space. Above all, we recommend having water in the toilet prior to flushing solids and toilet paper.

Flush toilet on a restroom trailer

To flush, press pedal down until it contacts the floor. Release pedal after complete flush.

• If disposing liquids, press the pedal for 1-2 seconds.

• When dumping solids in a restroom trailer, press pedal until contents are rinsed from bowl. Flushing longer than necessary will cause holding tank to fill too quickly.

A small amount of water will collect in the bowl after a flush to create an airtight seal.


To prevent holding tank odors from entering the living space, make sure a small amount of water remains in the toilet bowl of the restroom trailer.

There are two ways to monitor the waste level in the Rich Specialty Trailer waste tank.  Either with an electric monitor or visually with a site glass. The restroom trailer offers an electrical sensor which determines how full the tank is. This monitor panel, located in the trailer mechanical room has a sensor board with 5 lights, which will show whether the tank is E (empty), ¼ (1/4 full), ½ (½ full), ¾ (3/4 full), or F (tank if full). One of these lights will come on when you push the trailer “TANK” button. Before the monitor can operate it must be calibrated with the tank empty and with the tank full.

The electrical sensor monitor should be calibrated with the trailer as close to level as possible.  Depending on where the sensor strips are located on the restroom trailer tank, the readings may be somewhat sensitive to the pitch of the vehicle (due to the fluid sloshing either against or away from the sensor elements mounted to the tank wall). Keep this in mind when interpreting what otherwise might be a malfunctioning sensor or display.



This monitor panel in the trailer features a smart chip calibration algorithm.

Note: You can calibrate either empty or full first, but you need to have the tank at the level you want calibrated (i.e. empty for empty or full for full).

When you calibrate the empty level, start with an empty tank. Hold the tank reading button. While holding the tank reading button, press and hold the empty calibration button for 5 seconds (the button marked with an “E”) lights should then note you have an empty tank.

While calibrating the full level for the restroom trailer, fill the tank with water repeat the same procedures above but press the “F” button. The lights should then note when you have a full tank.

The second method to check the level of the restroom trailer tank is to simply open the rear door on the trailer to expose the tank. We build a site strip into the restroom trailer tank. Which will allow you to see the waste level against the rear of the tank.


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