Yup, it is legal. I pay for the water utility that I use, no matter if I get a thin stream or none at all. My local water authority isn't obligated to provide a minimum or maximum PSI to thier homes. I know people that get 165 PSI.
I have a P3 kill-a-watt meter. It averages about 770 - 790 watts. I rounded off to the rated 800 watts. The pump is set at the factory to cut in at 25 PSI and cut off at 55 PSI. The city line is at 7 PSI, so once the pressure tank is empty the pump will always fire.
So I got the booster pump and connected to the hot side for now, because it was the most accessible at the moment. The pressure tank holds about 2 gallons of water and between the cut in and cut out, the pump runs for about 25 seconds at about 800 watts.
So, assuming I use 100 gallons of water...
I have found a 800 Watt with a factory set 28/50 PSI pressure switch and a 4 gallon pressure tank. It's the most economical one I could find and easily available at my local Sam's Club for $200 bucks.
Where I live, the water pressure from the water utility is very low (About 8 PSI average). I am considering getting a jet pump with a 33 gallon pressure tank and a 400 gallon water tank for when there is no water at all. Electricity is a major concern because it is very expensive in my area...
