The Water Supply Sustainability Indicator (WSSI) indicates how sustainable the overall water supply is for a parcel of land.
The Water Supply Sustainability Indicator (WSSI) is a proprietary score created to indicate how sustainable the overall water district water supply and GSA groundwater availability is for a parcel of land. The score utilizes the average surface water supply over the last 10 years from the water district and adds that number to the available groundwater (or restriction for the current year) from the GSA to then create a scale based score from 1-7 with each value corresponding to a range of acre-feet per acre. Each WSSI score has a corresponding description that helps you understand how the parcel will fare in most water year types (wet, dry, etc.) with permanent plantings or row crops and is currently only available in the state of California.
For more information, including WSSI Methodology and an example calculation, please visit the WSSI Data FAQ