When I bought a house in the Rio Grande Valley of Texas in the 1980s, the previous owner had rerouted the drains for the kitchen sink and bathroom shower to run along the sides of the house, where he had gardens, using a drip system to water all the plants along the way, including an orange tree, which is where everything that hadn't dripped out along the way went. When I bought the house, he offered to reconnect it to the city water, given that rerouting it like that wasn't exactly up to code, but it seemed like a good idea to me. It was a good idea. Given the heat that we'd have in the Valley, that was an excellent way of watering the plants. Of course, I had to make sure that I used soaps and shampoos that were environmentally friendly, and not to dump any nasty stuff into my drain. Of course, if I wanted to dump nasty stuff into the drain, I had another bathroom and a utility sink where I could do that. That probably wouldn't be such a good idea in Maine, given that we'd have a thick, solid sheet of ice all the way around the house, but it worked well in Texas.