Completed annual backflow prevention assembly testing at commercial property today. Tested double check valve assembly on main water service (3" Watts #007). Both check valves holding tight at required PSI. No leaks observed from relief valve. All test cocks functioning properly. Cleaned minor debris from strainer. Updated certification tags and submitted paperwork to city water department. Device is operating within specifications and protecting water supply. Recommended monitoring pressure fluctuations after recent street work in area.