Water Pressure Pump Location

Question

We would like to increase the hot water pressure in our home to increase the flow rate in our upstairs shower.

We are in California on city water (no well). I spoke with the water company and they said we are on a gravity fed system and it is not possible for them to increase the water pressure. They calculated the water pressure at our tap at 38-43 PSI.

I have done the following:

• Pressure regulator valve (located near hose bib in front of house before water pipe enters the home) is wide open (maxed out at 80 PSI).
• Water pressure at hose bib in front of house, after the PRV, before entering the house is 38-40 PSI.
• Water pressure at cold water inlet to the tank hot water heater is also 38-40 PSI.
• I bypassed the water heater by connecting the cold water inlet flex hose to the hot water pipe going into the house and the water flow was the same at the upstairs shower. This rules out an issue with the water heater.
• Removed shower head and observed same slow flow rate. It's not the shower head.
• Checked aerators at faucets and did not find any significant deposits.

I am considering installing a water pressure pump (like SEAFLO 33-Series or similar, or a more expensive Davey brand pump). Some questions:

1. Would such a pump improve our hot water pressure for our home?
2. Do I need a water holding tank for such a pump, or can it work without it?
3. If I'm just trying to increase the hot water pressure, where should I install it - before the cold water inlet to the hot water tank, or after the hot water outlet of the water tank?
4. What type of lifespan should I expect from these pumps?

Answer 1

If the PRV is adjustable (most are) crank it up! Normally turning the adjustment screw clockwise will increase the pressure. If you have a pressure gauge crank it to 60 most well systems I set up are 40/60 but city water I usually set 60 as a minimum. The increased pressure will increase the flow the pressure depends on the height of the tank but if you have 80 psi outside you should be able to get the same or a reasonable 60 psi in the home by increasing the Spring tension on the PRV (PRV is a fancy name for a pressure regulator they need to be made for potable (drinking) water systems but that’s all they are) increase the spring pressure and your pressure increases.

Answer 2

If you're only getting ~40PSI from the water company and you find that insufficient, then yes, installing a pump is the only way to actually increase your pressure.

If you only want it on the hot water side, then I'd suggest installing it just before the hot water heater. Find out what the maximum inlet pressure for you heater is and ensure that your pump doesn't exceed this rating. If you install it on the outlet side, you will, most likely, suck water out of the tank faster than the incoming cold can fill it. This could lead to the tank emptying enough that the heating elements (especially if electric) become exposed and burn out, requiring replacement.

Do note that putting a pump on the hot water is going to increase the rate at which you use hot water and that your showers, while more satisfying with higher pressure, will also have to be shorter because you'll run out of hot water more quickly. Dish and clothes washers shouldn't be effected by this since they fill based on volume of water, and they'll simply fill to that volume level more quickly.

Also, if only the hot water side is pressurized, be aware that you may have trouble balancing hot & cold to find a reasonable temperature since you'll be getting more hot than cold coming to each faucet. You may have trouble getting enough cold water flow to acceptably cool the hot water coming in.