text:  You don't need a licensed plumber to do this. Now that's not to say that a licensed plumber couldn't do it, but by law, you're not required to have it. If this was on the main water supply of the house and the drinking water and all of that, especially being on a hillside, you don't want to do anything that you could contaminate your neighbor's water by back draining something the wrong way into the system, right?