Tucson Commercial Rainwater Harvesting

Purpose of the ordinance is to increase the use of harvested rainwater at commercial sites in Tucson and to decrease use of potable and reclaimed water supplies. Rainwater harvesting is a useful strategy for providing supplemental irrigation water to commercial landscapes, making more efficient use of the desert’s most limited resource – water. A key requirement is to meet 50% of landscape water demand using harvested water.

This standard provides:
A. Design considerations and technical requirements for passive and active water harvesting systems;
B. Requirements and guidelines for the preparation and implementation of Rainwater Harvesting Plans;
C. Requirements for landscape and irrigation at water harvesting sites;
D. Recommended maintenance steps;
E. Elements required for compliance with the ordinance;
F. Enforcement provisions;
G. Water budget assumptions and calculations (Exhibit A); and,
H. Annual reporting form (Exhibit B).

Code recognizes that Water Harvesting Infiltration Areas can include exposed soil shaped to hold and infiltrate water, permeable soil subgrades overlain with impervious pavement that receive water via perforated pipes or other conveyance techniques, structured soil overlain with permeable paving, and other strategies that collect water and allow it to soak into the subsurface to support landscape plants. Requires first flush retention.