The National Fire Protection Association publishes NFPA 25 Inspection, Testing and Maintenance of Water Based Fire Protection Systems. This document recommends that control valves without electronic supervision be checked on a weekly basis, just to make sure that they are in the open position. Other system components have different requirements. Check with the NFPA 25 or the manufacturers’ literature for details.
At least four times each year, a full sprinkler system inspection should be performed by a knowledgeable professional. Some states and cities require more frequent inspections. Most sprinkler contractors offer economical long term service agreements. These contractors can provide you with the test certificates which will comply with your insurance company and local fire department inspection requirements.