With the passage of the nation's first municipal rainwater harvesting ordinance for commercial projects, Tucson placed itself at the forefront of the national rainwater harvesting movement. The ordinance calls for 50 percent of water used for landscaping on new commercial properties to come from harvested rainwater. Looking forward, the law will require this proportion of water used in landscaping to be increased to 75 percent within three years of the property being legally occupied. The only U.S. law exceeding this scope in required rainwater harvesting is in the U.S. Virgin Islands, where no reliable underground fresh water source is available.