This Arizona project has landscaped exclusively with xeriscape materials. The local zoning authority requires an automated irrigation system and will not issue a building permit without one. Our intention is to use no potable water, via the mandated drip irrigation system, except during the plant establishment period and after that only in case of extreme drought where precipitation falls below "normal" anticipated rainfall (e.g. between 10/18/2005 and 03/11/2006 we experienced 144 continuous days of no precipitation-a period that averages 3.58"). We will install a dedicated water meter on the irrigation system and will log quarterly water meter readings and local precipitation records to verify the performance of the intent. The 8/16/2005 Ruling states, "WEc1.2 may be achieved (by)demonstrating that the quantity of \'normal\' anticipated rainfall meets 100% of your irrigation needs ... ,providing potable water as a backup is acceptable". We have met the credit intent with our xeriscape landscape palette, as well as provided a method of verification of continued performance via data logging. Since a permanent irrigation system is mandated by zoning, it would be onerous and wasteful to spend money, time and resources to design and build a parallel captured rainwater or recycled water system. We cannot eliminate the permanent irrigation system due to zoning restrictions, and since our intent is to only use it to supply potable water for establishing plantings and as a drought backup, we believe we have met the full intent of the credit.
The project is inquiring if it is possible to achieve WEc1.2 despite the installation of a permanent irrigation system which is required by the local zoning authority in Arizona. The project\'s xeriscape landscaping, as described, would only need to be watered for initial plant establishment and in times of drought. Per CIR Ruling 4/4/2005, it is acceptable for projects to provide potable water as backup irrigation during extended dry periods. Since a permanent irrigation system was installed only to comply with the local zoning authority and not for on-going landscape irrigation, the project is eligible to achieve WEc1.2. For appropriate documentation, please be prepared to provide a listing of the xeriscape plants incorporated into the site landscape, their water needs, and the monthly average rainfall for the project\'s location. The project should also provide evidence of the local zoning authority\'s requirement to install a permanent irrigation system. Note: This interpretation is specific to your project description and does not establish precedent that other projects with permanent irrigation systems will be acceptable for achievement of WEc1.2.