PDFWAC 173-517-180
Measuring water use.
Each future new appropriation of groundwater or surface water, including permit-exempt well use, is required to install and maintain a measuring device (water meter) meeting specifications provided by ecology. The user must report to ecology, by December 31 of each year, meter readings demonstrating water use for the previous water year, October 1 through September 30, or as directed by ecology.