I've never understood it either, i.e. renting a water heater. Really? Does one rent their furnace? their kitchen appliances?Is it something in the water? Is it the catholic education system? What is it? What do they not get about capitalism? Why would you ever rent a hot water tank?
Mind you, I've also been bewildered about calling electricity "hydro". Does it look like water? Okay, I get that Adam Beck started the ball rolling (in a significant way) with hydro-electric electricity but seriously WTF is hydro? BC is almost entirely hydro-electricity with most of it delivered by BC Hydro but no one I know here calls those electrons hydro.
OTOH, maybe milk in bags is more manageable. Buy a Rubbermaid pitcher and that may be more convenient than a recyclable plastic (or waxed) carton. Y'all do strange stuff 'down east'.