Letting all the dishwater just run down the drain is such a waste. It's not hazardous and therefore still has purpose. While you wouldn't want to bathe in it, the fruit trees certainly don't mind being soaked by this greywater. Our county has codes for those folks who wish to put in an intricate system. We, on the other hand, prefer to do things a little more on the low-tech side. Here is our kitchen greywater "system":
Yup, just a bucket under the sink drain. It's that easy! When it fills up, we just walk it out to the yard and deposit the water under the trees. This is a great way to supplement our weekly irrigation and the "waste" water gets used for a good purpose.
Speaking of a good purpose, in the bathroom we have a similar set up. The water from the bathroom sink gets diverted to toilet flushing. With our low-flow toilet, it doesn't take much greywater to do the job.
We're also going to set up a catchment in the shower and put that water to good use. At our house in Austin we ran a hose from a sump pump out the exterior wall. Any water that was still sitting around at the end of the day got pumped out to the pecan trees. You don't want your greywater to sit around for more than a day, then it gets septic (and really stinky). We're not ready to drill another hole in the wall, so a tub in the shower will have to do.
In Austin we also hooked up our washing machine to a 50 gal trash can and put a spigot in the bottom. A hose was attached to the spigot and it ran out of the garage and to the large shade trees in the front yard. We would move the hose around after each load to make sure the trees were getting equal access to the water.
When we used this system before, it really brought to light just how much water we were using on a daily basis. When you're hauling out a five-gallon bucket sloshing-full of dishwater a few times a day, in all types of weather, you can't ignore your usage. As a family of 2, we don't use much, but greywater recycling was a great way to see how we could reduce our use even further.
It almost seems criminal given our drought conditions to just let this stuff head off to the water treatment plant after just one use. We need to stretch our water as far as it can go and this is one small way to accomplish that goal.