Under WRF project 4639, Level 1 Water Audit Validation, a manual was developed to provide guidance on Level 1 validation for audits prepared using the American Water Works Association (AWWA) Free Water Audit Software, Version 5. AWWA is in the process of developing the next version of the Free Water Audit Software, Version 6. This will be a major evolution in the tool, and likely will accelerate the tool's adoption as the industry standard for conducting top-down water audits. To address this new version of the software, this research will develop a new Level 1 validation guidance manual that sets the industry standard for Level 1 validation for audits prepared using Version 6 of the Free Water Audit Software. Research partners: California Department of Water Resources and State of Hawaii Commission on Water Research Management.