Water can cause big problems with electrical service equipment, especially your main breaker panel. It can enter into the outside meter box, causing rust and corrosion that can damage the connections and cause a safety hazard. Water can also make its way into the main breaker panel often coming in thru the service entrance cable.
It’s important that the insulation covering your service entrance cables are in good condition so water can’t penetrate. The picture below shows a old rusted out meterbox in Landenburg, PA. The top photo shows the replacement installation, featuring a 200 amp service.