if only two people are in a house, it's still the same amount of showers, flushing and tooth brushing regardless of how many bathrooms there are. Let's assume that the toilets don't run. You can have one running toilet that uses way more water than 5 low-toilets that never get used. You can have a 3000 ft sq house that is more energy efficient than an poorly built 1000 ft sq place with an old refrigerator and leaky windows. Appearances aren't everything.

So how do you balance what you want and what's appropriate? And who gets to decide what's appropriate?