Key Biscayne is a village at the end of the Rickenbacker Causeway, and the causeway is the only road on and off the island. That single link shapes the day: a bridge lift, a busy weekend at the toll plaza or an incident on the approach can add time to a visit for reasons that have nothing to do with the appliance.
One boulevard, two kinds of building
Almost everything runs off Crandon Boulevard, which carries traffic from the causeway down to the state park at the southern tip. West of it the streets are single-family, with driveways, garages and side utility rooms. East of it the buildings are condominium towers along the ocean, where closets are stacked on service balconies and fed from a shared riser. The same appliance sits in two very different rooms. In the houses it is usually in the garage, an exterior closet or a utility room off the carport. In the towers it is behind a louvred door on a balcony, next to the air handler.
Salt spray does its damage first
Ocean-side buildings take spray on any windy day, not only in a storm. On an exterior closet that shows up as corrosion on the flue collar, the gas union and the electrical cover long before it shows up as a fault. The tank itself usually fails from the inside, at the anode or through the shell, while the fittings around it are failing from the outside. Both get inspected, because a replacement that reuses a corroded connector will not last the life of the new unit.
The water is mainland water and carries the same minerals as the rest of the county, so scale on elements and tank floors is ordinary here and a rumbling tank is a common complaint rather than an odd one.
Permits and building access
Key Biscayne is its own municipality, so a replacement is permitted through the Village rather than the City of Miami. Work in a tower also needs the manager's agreement on the service elevator and on any shutdown if the riser has to be isolated. Start on the contact page and say which side of the boulevard you are on, the house streets or a tower.