Hyde Park's housing is old enough to have been through several renovations, and each renovation tends to move the water heater somewhere new. It is not unusual to find a tank in a converted porch, a crawl space or a utility nook added at the back of the house.
Renovated homes also bring tankless conversions. A gas tankless unit needs a larger gas supply and a different vent than the tank it replaces, and an older house may need an electrical upgrade for the controls. Those are checked before the unit is specified, not after it is on the wall.
Crawl-space installations need a clear leak response. Water under a house does not announce itself, and by the time it is noticed the insulation and subfloor may already be affected. The first visit therefore includes a look at the ground beneath the unit, not just the appliance.
Humidity near the bay is a factor for units in crawl spaces and converted porches. Damp air accelerates corrosion on fittings and vent connectors, and a crawl-space install that stays wet will keep eating anode material faster than one in a dry garage. Ventilation and drainage get as much attention as the appliance.