The ability to take a hot shower where ever you happen to stop driving for the night is not optional. That said, the rig's water system is pretty straightforward with only a few clever hacks and features.

It all starts of course with our potable water tank. I'm not sure how big it is, maybe 30-40 gallons and it's attached to a 12V water pump that provides the pressure to the rest of the system.

There are two primary places in my rig water needs to be available: The kitchen sink, and the bathroom. Both need hot and cold water available.

The rig has a single water hookup using a standard hose attachment. This hookup first goes through a high-flow water filter to set a baseline water quality, then through a pressure regulator to ensure the pressure doesn't exceed the plumbing of the RV.

Next, the water can either go into the water tank (to refill), or can be diverted into the main plumbing system.

If using tank water, a 12V pressure-sensing pump is used to provide water pressure. Prior to that pump is a strainer to ensure nothing weird from the tank gets sucked into the pump.

From there, the cold water is distributed throughout the RV as needed as well as connected to the tankless water heater. The heater is equipped with a bypass valve to prevent damage to the heater when winterizing (or just to provide water to all sources even though hot might not be available due to a lack of propane).

For the toilet and the clothes washer, check valves are installed prior to reaching their destination in order to prevent any sort of back-flow of potentially contaminated water into the fresh water system. These are of course unncessary for sinks, where there is no way for water to back-flow into the fresh water pipes.

The bathroom in the rig is a combination bathroom, sink area, and shower. Instead of a normal "shower pan" at the bottom of a stand-alone shower, I've installed a pond-liner with that slopes to a drain that connects to my gray water tank for disposal. On top of this pond-liner are slats of water-protected/stained wood that make up the actual floor of the space. In this way, you could pour a glass of water on the floor and it would go into the gray tank.

Of course the walls are all made of waterproof material and on top of this floor is your standard gravity-toilet.

For the shower and sink, I purchased a wall-mounted diverter that can either send water to the sink or to the shower head. The idea being you can get the temp of your water how you like it in the sink and then turn on the shower and get yourself clean. Or, maybe you just wanted to brush your teeth!

Hot water is provided to the RV via a small tankless water heater that heats the water via propane. Like all tankless water heaters, cold water goes in and comes out hot in basically real-time. This hot line is then fed to both the kitchen sink and diverter for the bathroom.

In addition to the water pump that provides pressure from the water tank to the plumbing (when not connected to city water) a second water pump is installed at the farthest point from the hot water (kitchen sink) and attached to an IoT sensor and relay. This pump when activated cycles water from the hot water line back into the cold water lines to re-heat it.

The reason this is done is to reduce the amount of water from the tank wasted down the drain waiting for the hot water to "heat up" from the hot water heater. Instead the temperature of the water is monitored and when necessary the pump is turned on.

As an IoT device, this feature can be enabled or disabled automatically based on time of day or software switch (for example, no need to waste propane heating water when

When using the RV in sub-zero temperatures, just because the actual cabin of the RV might be comfortable it doesn't mean the water tank and lines from it aren't at risk for freezing since they are outside the heated area. For this, a number of things are done:

When connecting to shore water, a off-the shelf heated shore water line ensures it doesn't freeze between the shore and my RV.

I have installed a 12V water compartment heater designed to just keep the temperature of the compartment above freezing. This is complemented by a temperature sensor within the compartment to ensure that's the case.

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