Second Caveat: Do not allow your greywater to overflow onto your neighbor’s veg. patch. It’s not healthy and, here in Oregon, enforcement is on a complaint based system. No one complains, no letter asking you to cease and desist.
That being said, I’m glad no one measures the outflow of water from our house in the summertime. Very little leaves the property. I hate to waste things, including water.
We used to have a fairly complex system of capturing the shower and laundry water based upon some modest changes in plumbing, two fifty five gallon blue plastic barrels that smell faintly of tamari, and a small water pump. After three showers, the water was pumped up from the basement and poured on the flower beds. It worked, but it had some flaws. The barrels overflowed occasionally, the water smelled a little skuzzy, and Mark was always muttering about the carbon footprint of the pump, as well as the loud, growly, squeally noise it made while pumping. Then, while walking home one afternoon, I spotted an old tub by the side of the road. “Free” the sign proclaimed. We hauled it to the backyard, built a shelter around it using old wood from a shed, plumbed it with a hose that reaches to the basement utility sink, and attached a short drainage hose to the bottom. Total cost—35$ and two trips to Searing Plumbing and Electric, where they did not give me a funny look when I came in with my questions. Hot water shower. Drains directly into the flower beds. No need for the pump. No nasty smell in the basement. As soon as Mark realized that, when he used the outdoor shower, he did not have to clean the indoor tub every week, he was sold. We stuck with the barrel and pump system for the laundry, but, as that works out to one barrel for four loads, I usually drain it while hanging the last load. No smell. The dish water has always been simple. One dish pan. One five gallon bucket. One chart, complete with flamingo fridge magnet, charting where the water is to be poured next.
There are a few common sense ideas to keep in mind when considering greywater. First, figure out a way for the water to drain quickly into the ground, rather than sitting around, breeding who knows what. Second, don’t pour it directly on plants you plan on eating soon. Third, think about your soaps. They need to biodegrade. Here in Oregon, I don’t worry about build up in the soil; the long slow rains leach everything else out of the soil, so why not a little soap residue? If I lived in a drier climate, I might need to consider the issue. Finally, watch what the water washes—laundry water that washed diapers might not be ideal for flower beds and fruit trees, even. There is a great, inexpensive book on greywater systems by Oasis. We poured over it for several years before loaning it out to someone. You can do all kinds of cool things with your household water, establishing wetlands with reeds to filter the water before it seeps into the ground. However, after all of our experiments, the simpler the system, the more likely you are to use it.