I heard that reverse osmosis water filters waste a lot of water. Is that true? [Reverse Osmosis FAQ's]

It costs less than 2 cents per gallon of purified water (vs. water stores $0.25/gallon)

Let's do a simple math problem: 

In this water bill, City charges $2.04/unit of water (1 unit = 748.1gals); therefore, each gallon of water costs $2.04/748.01gals = $0.0027/gal (Note: two zeros, less than 1 cent!!!)

R.O. Water Filters produce purified water typically in 4:1 to 8:1 ratio (drains 4-8 gallons to get 1 gallon of purified water).

Let's take the average number of 6:1 ratio - to get 1 gallon of purified water, the R.O. Unit drains 6 gallons, which is 6 gallons x $0.0027/gal = $0.016 (less than 2 cents).

That's how water stores make money:   $0.02/gallon vs. $0.25/gallon

Therefore, if you really love your husband, buy an RO Water Filter now, before he gets back pain (because of carying heavy water bottles from store)