Performed Cma inspection on 5 rooftop gas package systems. All systems cooling properly at this time. Contact (Dean) stated System 2 leaks when raining. Requests resealing of unit/rooftop. Did not observe any cause for leaking. Maintenance tech not equipped to search in depth for cause of leak. Added silicone sealant to top seal on unit access doors. System should be monitored for leaking at next rainfall. Unit may be in need of in depth leak search.