A mobile shower trailer works like a small building on wheels with its own plumbing, hot water, drainage and power. Clean water comes in from a hose or an onboard fresh water tank, a water heater warms it on demand, and the used shower water (gray water) drains into a holding tank or straight into a sewer tap. A shore power cord runs the lights, controls and the roof-mounted air conditioner with heat, so each shower room stays comfortable in any season.
That is the short answer. If you are buying a trailer for a crew, a camp or a response team, the details behind each of those systems decide how many people the trailer can serve, how often it needs service and what your site has to provide. Here is how each part works on the trailers we build in De Queen, Arkansas.
The four systems inside a shower trailer
Every shower trailer, from a single room to ten shower units, comes down to four systems working together:
- Fresh water supply: how clean water gets into the trailer.
- Hot water: how that water is heated for each shower.
- Drainage: where the used water goes.
- Power and climate: what keeps the lights, controls and room temperature running.
Most of the equipment sits in a mechanical room or equipment bay, behind its own exterior door, so service work happens outside the shower rooms.
Fresh water: hose hook-up or onboard tank
A shower trailer gets its water one of two ways. On a site with a water supply, a hose connects to the fresh water hook-up on the side of the trailer and the trailer runs from that supply. On a remote site, the trailer draws from an onboard fresh water tank that is filled before use and refilled as needed. Trailers that run from a tank use a pump to pressurize the lines, so the showers and sinks feel like a normal bathroom.
Tank size is one of the most important choices you make. On our 2 room shower and restroom combo trailer, for example, a 200-gallon fresh water tank is offered as an upgrade for more capacity. A bigger tank means fewer refills between service visits, which matters most where water has to be trucked in. Our Alpha Series trailers use 3/8-inch HDPE extrusion-welded tanks.
If you are still deciding which setup fits your site, our guide to self-contained versus hookup trailer setups walks through the trade-offs in more detail.
Hot water: on-demand heating
Hot water is what separates a shower trailer from a basic wash station. Our Alpha Series mobile shower trailers use propane on-demand water heating with a timed run cycle. Instead of storing a large tank of hot water, an on-demand (tankless) heater warms water as it flows, so the supply does not run out after a few showers the way a small storage heater can.
The propane comes from LP bottles mounted on the trailer. The 2 room combo unit, for instance, carries two 30 lb LP bottles in a rack and an on-demand tankless water heater as standard. An electric hot water heater is also available as an add-on for the sink stations.
Two things are worth planning for:
- Propane supply. Someone needs to check and swap or refill the LP bottles on a schedule that matches how heavily the showers are used.
- Timed showers. A timed run cycle and self-closing shower faucets help control how much water each person uses, which stretches the fresh water tank and the gray water tank on a remote site.
Drainage: where the gray water goes
This is the question most first-time buyers ask, and the answer is simple. Water from the showers and sinks is gray water. It is collected in a tank on the trailer or sent directly into a sewer tap, depending on the site. Our shower trailers are direct sewer hook-up capable, so the same trailer can work on a connected site or a remote one.
On a tank setup, the waste tank has an LED level indicator so whoever services the trailer can see when it needs to be emptied. A 3-inch quick-connect valve lets a pump truck drain the tank, and a 1-inch washout plug is there for rinsing it out. Floor drains are available as an add-on for easier washdown of the rooms.
On a combo trailer, where each private room has a toilet as well as a shower, the waste side has to handle toilet waste too. That is why tank capacity and pump-out frequency should be part of the conversation before you order, not after the trailer is on site.
Power and climate control
A shower trailer plugs into site power or a generator through a shore-style power cord. That power runs the 12-volt LED lighting, the controls and the climate system. Every trailer we build ships with a roof-mounted air conditioner with heat, and a wall-mounted climate control box sits in the mechanical room. On the Alpha Series showers, conditioned air is ducted into the rooms through a one-piece ceiling with built-in supply and return.
For sites without dependable power, a solar panel package is offered as an upgrade for off-grid use, and we confirm those options with you during the build.
Cold weather adds a fifth concern: keeping water from freezing. For sites that stay below freezing, we offer winterization packages and an Arctic package on certain units, which adds a 25,000 BTU furnace, extra insulation, a waste tank de-icing system, a 50-foot heated water hose and a 50-amp power cord upgrade. Our page on heated restroom and shower trailers explains which level of protection fits which climate.
What happens inside each shower room
From the user's side, a good shower trailer should feel like a clean, private bathroom. On our Alpha Series units, each room includes a fiberglass shower pan, a self-closing shower faucet, a shower curtain and a shampoo and soap dispenser. The walls are smooth laminated or white commercial FRP, the floor is one-piece non-skid rubber, and the rooms are air-conditioned and heated through ducted vents.
Layouts vary with the job. We build shower trailers from one to ten shower units, with options for changing areas, benches, lockers, towel and equipment storage, hand wash stations, and public or private rooms. If every room also needs a toilet, a 2 room shower and restroom combo trailer puts a toilet and a shower behind each private door in a 12-foot by 6-foot trailer.
Planning the setup on your site
Knowing how the systems work makes site planning straightforward. Before your trailer arrives, check these points:
- Water source. Is there a hose connection close by, or will the fresh water tank be filled by truck?
- Drainage. Is there a sewer tap you can connect to, or will the gray water tank be pumped out on a schedule?
- Power. Is site power available, or will you run a generator? Make sure it matches the trailer's power cord.
- Propane. Who will check and refill the LP bottles for the water heater?
- Access. Can a water truck and a pump truck reach the trailer's hook-ups and the mechanical room door?
- Level ground. Is there a level, firm spot so the steps sit safely and drains flow properly?
For job sites, the federal construction sanitation standard, OSHA 29 CFR 1926.51, sets out what showers must provide when a particular standard requires them, including hot and cold water feeding a common discharge line and one shower for each 10 employees of each sex who must shower during the same shift. We build trailers to align with OSHA sanitation guidelines; check with your own safety team on what applies to your job.
Frequently asked questions
How does a mobile shower trailer get hot water?
Our Alpha Series shower trailers use propane on-demand water heating with a timed run cycle. The heater warms water as it flows instead of storing it, and the propane comes from LP bottles mounted on the trailer.
Where does the water drain in a shower trailer?
Gray water from the showers and sinks is collected in a tank on the trailer or dumped into a sewer tap, depending on the site. Tank setups are emptied through a quick-connect waste valve by a pump truck.
Does a shower trailer need to be hooked up to water?
No. A trailer can run from a hose connection where water is available, or from an onboard fresh water tank on a remote site. Larger tanks are available on some models for longer runs between refills.
Can a shower trailer be used in freezing weather?
Yes, with the right package. Every trailer has a roof-mounted air conditioner with heat, and freezing sites add a winterization package or the Arctic package with a furnace, extra insulation and tank de-icing.
Can a shower trailer include toilets?
Yes. Our combo trailers put a toilet and a shower in each private room, so one trailer covers both needs.
Build the shower trailer your site needs
Every shower trailer we build is configured to your crew size, water source, drainage and climate, and we sell nationwide. Tell us what you need and we will quote it. Build your trailer in a few steps, or call (800) 789-1212, Mon to Fri 9 to 5 CT. We build and sell trailers. We do not rent them.
Keep reading: Shower and Restroom Trailers for Workforce Housing and Remote Crews, Self-Contained vs. Hookup Restroom Trailers: Which Setup Is Right for You? and Restroom Trailer Buying Checklist for Fleet Owners.