There are multiple options for plumbing your Airstream as far as layouts and materials used, therefore each setup will probably be a little different. Once the tanks, water heater and pumps are connected, adding new faucets and appliances is very easy.
Below is the diagram that I based my plumbing arrangement on. I did add an additional hands-free bathroom faucet and a washing machine attached to the main line at the end after the shower in the diagram. I’ll explain more about those below, but I’d suggest printing this diagram to refer to as you are plumbing your project.
I ran all my plumbing lines inside the actual trailer because of the frigid temperatures we endure here in South Eastern Ontario during the winter. This was also the reason that I chose to use Pex pipe which does not crack or burst like copper. I went with half inch Pex, which you can get in white, red or blue to determine your hot from cold lines. I also used shark bite fittings. They are more expensive, but pretty much foolproof and if you don’t have experience in plumbing, it may be worth spending the extra.
Even with the shark bites, there will be some parts that require crimp rings and a crimper so have those tools on hand as well.
I installed my hot water heater, and pump directly under the kitchen sink and the fresh water tank is directly below that. The hot water heater vents through the floor and is about 6-8 inches underneath from the trailers edge. The two white Pex lines sticking up in the first image below are plumbed to the fresh water tank. The images that follow show how we installed the under mount kitchen sink above the heater and pump.
The PVC drain pipe is gravity fed so make sure you have a slight decline leading to your grey tank. Going from the kitchen sink to the grey tank on a trailer this size will likely be around 12-15 feet of distance. The white and red Pex are the hot and cold lines running to the bathroom at the rear. (The grey tank is directly under the bathroom floor) The last two photos in this sequence show an adapter from the PVC pipe. I used this because I will be draining the water into a much narrower flexible tube so that I can plumb it into the same drain that the shower will use. Standard PVC would be much too big for that.
Below are some photos under the kitchen sink showing the pump and the PVC drain out, the main connection from the city water inlet, and the hot and cold water tap valves for the kitchen faucet. The last photo shows the connections finalized. (It needs a bit of tidying up but at least you can see the connections)
The wall frame below separates the bathroom from the rest of the trailer and it will house the lines and valve for the shower. The Pex will run all the way to the back window where the bathroom sink and washing machine will connect. The second photo shows the wall partially installed with the shower spout and shower valve installed through the wall and the final photo is from the opposite side of the wall, where the bed will be. Because the wall is much thinner than a standard house wall, you may have to build an additional frame behind the wall in order to accommodate the shower valve and the shark bite connections.
We bought a fibreglass reinforced plastic shower base but had to build it up so as to fit the drain. We used pine 1×2 and thin plywood to build the base. Although its probably unnecessary, we coated all the wood with a waterproof sealant in case it is exposed to moisture or humidity in the bathroom. The second photo shows a stand we constructed in the shower which will support a bamboo seat, the Pex lines coming out will be plumbed to the bathroom sink. The grey tube is the venting hose for our composting toilet. Having a composting toilet eliminates the need for a black water tank and thus, a lot of extra plumbing. Once the wood shower base was constructed, we used more 1×2 to build around it. We will use FRP (fibreglass reinforced plastic) panels to build the shower walls.
This photo shows our main shower valve setup.
The shower base slants towards the drain, however to make it stable on the platform, we filled in the bottom with spray foam insulation. The second photo shows all of our extra 1×2 supports to surround the shower base and the third shows everything installed.
Here are a few photos of the FRP panels going in. The white strips are a plastic groove used to hold the panels. We also secured them to the wall using aluminum rivets and a PL Premium adhesive specifically for spray foam. The FRP panels are about 3 times as thick as the aluminum but are easy to bend with the curve of the wall and are not too heavy.
Below is the 1×2 structure for the sink and the bamboo counter. We’ve chosen a hands free faucet which can operate on AA batteries or be plugged in, the tricky part about these faucets is that they require a thermostatic mixing valve in order to get warm water. You can plumb them with only a hot water or cold water line, resulting in water that is either very hot or very cold. The mixing valve (See photo 3 below) allows you to control the temperature via a dial directly on the valve. For the summers, it will be set to cold and during the colder months we will mix the warm water in. The mixing valve then feeds into the box housing the mechanisms for the faucet.
This is an elongated handle that we installed on the valve that releases the grey water tank.
When the bathroom is completely finished I will do a separate post specifically for that, detailing how we treated the bamboo, finalized the vanity, storage ideas, composting toilet install, etc…