yes it can (i have one) but for us only on high demand (tub) that is has a problem. the more gallons per miniute the less it will be.we dont even notice a change on all the other taps.and you can not (unless you get a high demand) run more than one thing at once. But to have a never ending shower and never runing out of hot water is priceless we also save a lot on our power bill. I have a electric 2.5gpm electric and 3 people in a small house. i would never swich back to a tank again.