Sorry about the incomplete post.
I hit <SEND> before the thought was complete.....
In Southern Arizona, water's the important resource.
Easiest, ( and most successful ) is to save washing machine water.
Have the machine empty into a 55 gallon drum on the back porch.
The simplest use is to use the water to drip-feed the garden.
The more elaborate installations pump the water to an overhead holding tank.
From there, it's gravity fed to the toilets, where it's used to "flush".