Water Heater Replacement in DC Condo Bldg

I live in a medium-size condo building in DC (~85 units), and we are replacing one of our three electric water heaters (or possibly all three). Our current heaters are all Bradford M-II-120-54's, originally manufactured in February 2000. One of our heaters developed a significant leak, and we intend to replace at least that unit.

I don't know much about water heaters, so if anyone can help answer these questions, I would be very grateful:

(1) What is the average life expectancy for a commercial electric heater in a condo building? (anyone know anything about DC water quality?)

(2) What sort of questions should we try to answer before deciding what to purchase as a replacement and deciding how many to replace?

(3) Anyone know any good contractors in the DC area for replacing a water heater? (We have worked with Harvey Hottel and Capitol Boiler Works in the past).

Thanks in advance.

It probably had a 3 year warranty.

Commercial electrics are available in many combinations of voltage...240/277/480, and single phase or 3 phase; and simultaneous OR non-simultaneous wiring. You would need to have all these specifics to get a quote for a new one.