Map showing states with water harvesting legislation, statues, and programs: http://www.ncsl.org/research/environment-and-natural-resources/rainwater-harvesting.aspx#mapState-by-state
Resources and handbooks discussing types of regulations and how to implement them:
- http://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/EPA_gi_munichandbook_harvesting.pdf
- http://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/WERF_Regulatory%20and%20Incentive%20Systems.pdf
- http://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/AR_Local%20Water%20Policy%20Innovation.pdf
Tucson's Commercial Water Harvesting Ordinance: