Standard shower heads are rated at 2.5 gallons per minute (at 80 psi, a little higher than most houses’ water pressure). 1.5 gallon per minute models can provide a very nice shower (though quality varies, so check Consumer Reports or another reference). Over a ten-minute shower, that’s ten gallons saved. Given Aqua’s marginal charge for water and the cost of the gas to heat those ten gallons, that’s only about 12¢ in savings. But over 500 showers, that adds up to $60.