This week, we hit some major milestones!  We got all of our plumbing and electrical system up and running and finished installing all the wallboards and the stairs!  We are starting to see the light at the end of the tunnel!

Let's talk about our plumbing system.  The system allows for us to be attached to a pressurized city water supply or for us to feed from our own water tank, say if we were camping off-grid.  Here's what our system looks like and a list of the major components.

  1. Tankless Water Heater
  2. Propane Auto Changeover Regulator
  3. Cooktop Stove
  4. Shower Handle and Shower Head
  5. Kitchen Faucet
  6. Kitchen Sink
  7. Accumulator Tank
  8. Water Inlet
  9. Water Pump
  10. Pump Strainer
  11. Potable Water Tank

As you can see in some of the photos below, we built a sort of "utility cabinet" in the lowest portion of our storage stairs.  Here we are housing our water tank, water pump, battery, inverter, and breaker box.  Our water and electrical inlets also enter the house in this area.  From here, the plumbing leaves the water pump (or straight from the pressurized inlet sourced from city water) and heads into the kitchen cabinets and over toward the bathroom.  We hid the water lines in the bathroom ceiling and installed the water heater on the bathroom wall above the toilet.  The water heater is propane fueled and wall-mounted.  Because it is an instantaneous heater, there is no water stored in the unit.  This makes it very compact and lightweight.  The vent on the top of the unit is routed straight out the wall on the side of the house. 

We purchased a shower head that has a hose and a "pause" button, since we will be trying to conserve water any time we are on our tank supply.  We also chose a kitchen faucet with a pull-down sprayer for this same reason.  

We chose to use PEX for all our pressurized water lines.  PEX is super easy to work with, since it's fairly flexible, the fittings crimp on simply with the proper tool, and we had no problems with leaks.  Unfortunately, we did encounter some leaks on some of our threaded brass fittings, particularly when transitioning from the tank, pump, and faucets. When we tested all our lines we found these to be the least reliable points. We ended up using a PTFE thread sealant in conjunction with teflon tape, which seemed to fix all those issues.

As far as drain lines, we used all PVC pipe that connects together under the house. The main drain line is then finished off with a fitting for connecting to standard RV sewer lines. The kitchen sink drains through a standard p-trap purchased from a hardware store but because the shower stall sits directly on the subfloor with only the thickness of the trailer deck below, a standard p-trap won't fit unless it drops well below the trailer deck. To avoid scraping a low hanging trap on anything that might be under the trailer, we decided to use an in-line trap. This is essentially a check valve in the line that allows water to flow one direction and doesn't allow any sewer gasses to travel back up. We'll have to put this through a series of tests once in use to see how well it works, but for now it seemed like the best option.  Most full-size houses have a stack vent, which is just a large pipe that extends vertically up and out of the house to allow air into the house's plumbing system for easy drainage.  Rather than this larger installation, we purchased an air admittance valve, which connects right under our kitchen sink and serves the same purpose.  The only disadvantage is that a regular stack vent also allows any sewer gases in the system to escape.  We don't have this, but we also don't anticipate this to be a major problem in such a small system.

For the propane system, we chose to use flexible stainless steel tubing, rather than black iron pipe which is more typical in larger installations.  We found the flexible tubing and fittings very easy to install and had no trouble with propane leaks when testing the system.  The only propane we're using in our house is for the water heater and the stove top.  We looked into purchasing a dual propane/electric fridge, but determined that a normal, all-electric fridge draws so little power that the advantage of having a propane fridge does not justify the cost of purchasing one.  We'll talk more about how the fridge fits into our battery system in the next post!

Doing the plumbing ourselves was definitely a learning experience for us and proved to be one of the more frustrating projects to date. Between finding the right fittings to transition between components, working in tight spaces, tracking down and resolving any leaks, and routing all the piping (especially drain lines that penetrated the subfloor), plumbing was certainly not a simple task and we are both glad to be done with it!