How to collect & use kitchen grey water to conserve water and water your garden all at once!
1. Soap* up/scrub your dishes:
2. Put a big pot in your sink:
3. Start rinsing your dishes:
4. Mmmm, dirty dish water**:
5. Let cool a bit if you used very hot water, then water plants of your choice***:
Do look up the grey water regulations in your area, at least so you know them. Read up a bit more on greywater systems. This may or may not be legal in your area, but understanding why it is or isn't can help you decide how to safely incorporate water reuse into your life.
One of the common big ones is that your not allowed to just let the water sit there, or pool on the ground. A common tactic is to divert the water below the surface of the soil, which can be accomplished easily. Some people don't want you to use kitchen grey water because of concerns around bacterial contamination from raw meat, etc, so consider how you're going to deal with that.
* don't use chlorine or borax (I don't know anyone who does for dishes, but you can't be sure on the internet). If you're quite concerned about your soap, get one that's labeled environmentally friendly or whatever.
** I'm a vegan so I don't have to worry about this, but if you're not, make sure you don't use waste water from dishes that had contact with raw meat or eggs. Because of potential bacterial contamination.
*** soap is basic, so don't water acid-loving plants with this. Never allow the water to pool for any length of time. Here you can see that I'm watering a cucurbit, which are thirsty plants that appreciate extra nutrients.