A flowchart has been developed to help understand the RWH requirements. The specific requirements are:
1. Active rainwater harvesting systems are mandatory, with a storage tank sized to capture a minimum of 1" of rainfall from the roof, or to provide anticipated annual landscaping water demand, whichever is less, for new developments (including those less than 1/4 acre) other than single family residential.
- In cases in which the developer uses exclusively native/drought-tolerant plants in compliance with Landscaping Standards and utilizes passive rainwater harvesting; or,
- Where landscaping water demand can be met through other sources of non-potable water
- In areas of food production, such as community gardens.
2. Single family residential shall utilize passive rainwater harvesting techniques for all new single family dwellings. Roof downspouts, if utilized, shall be directed to landscape and/or natural areas and no direct connection of downspouts to the street, right-of-way or any property line shall be allowed. For driveways that slope to the street, right-of-way or property line, efforts shall be made, insofar as practical, to direct driveway flows into natural or landscape areas. The "Residential Rainwater Harvesting: A Guide to Water-Wise Planning and Design" publication provided by the City of Flagstaff shall be utilized to meet this requirement.
LID Guidance Manual Chapter 6: Active Rainwater Harvesting