The basics of plumbing are very easy to learn. I went out and bought a 1/2" PEX crimper, and ran all of my water lines at 1/2". The water system starts at the water inlet, then flows into the tank. I used a 102 US Gallon tank which tucked nicely underneath the stairs. From there the line splits two ways. The first to a 1.5" drain valve in case I wanted to drain the system. The second went to the water system, which consisted of a SHURflo strainer, 120V pump, and accumulator.
In my small house, water feeds the kitchen sink and the bathroom shower. I use an Eccotemp tankless propane heater to supply the hot water.
For waste, I opted for a Nature's Head Composting Toilet; it is manufactured in the US, and built very well.