I've read that a great way to conserve water for use on your lawn is by
using the gray water from the washing machine. How is this conversion done? Can it be done in our home or does it have to be done when building? Ours is brick.
You will need to check your local regulations regarding the use of gray water as it may be illegal in your area to use it or it may have different treatment requirements prior to use. Possible sources of regulation would be local ordinances, the local plumbing code, and the state environmental department (or possibly county).
Also, spray irrigation is usually not allowed, only flood and drip type.