What is a good water pressure for residential use. We are on city water, and we had a bunch of remodeling done, and my wife is constantly complaining about the water pressure upstairs. Can I rig up something like a gauge from an air compressor to test it, or how is the best way for a homeowner?
The plumber installed “pex” 1/2″ lines to everthing in our upstairs, and I wonder if he should have run 3/4″ to get us enough volume. I guess it could have something to do with all the “low Flow” fixtures that are mandated, but I thought I would ask you folks for your ideas.
Thanks!
Replies
Get a gauge rated for water, not air. You should be able to pick one up at a place that sells water pump supplies, if your local HW store doesn't have one. Get fittings to attach to the outside hose bib or to laundry hose bib. In a pinch you can use the fittings that attach it in place of a faucet aeriator. (If attaching to an outside faucet, be sure it's not on the "wrong" side of a pressure reducer or backflow prevention valve.)
Critical measures are water pressure with all faucets turned off, and water pressure with one or two turned on. If the pressure is relatively constant between then the problem is pressure from the main. If pressure is quite a bit different (more than about 20%, I would guess), then the problem is resistance in the lines (possibly a valve not open somewhere, or a clogged water softener or some such).
A good target pressure is somewhere in the range of 50-65 pounds. Poor pressure would be below 30-25 pounds.
40 psi is barely adequate, but it would feel low if you are used to a higher pressure from somewhere else. 50 to 60 is good pressure. 80 is verging on too high.
You can check the pressure just as you said, by attaching a pressure gauge to a fitting somewhere in your house. Pressure is affected by elevation, it drops 4.3 psi for every 10 foot increase in elevation. So, you could be around 8 to 10 psi lower on the second floor than in the basement. Measuring pressure this way measures static pressure, that is, pressure when the water is not moving. The pressure will drop when water is flowing. If the pipes are too small or clogged, you won't get the volume from your fixtures and the pressure will be considerably lower at the fixture than at the supply.
Half-inch lines are normal and should be adequate unless you have low supply pressure or are trying to fill a large soaking tub.
Here are a couple of things to check. Often after plumbing work you'll get dirt clogging your faucet aerators. To clean them, shut the drain (so you don't loose the parts) and unscrew the aerator, separate the parts, and clean them off. Then reinstall them. For your shower, many shower heads' flow restrictors are a disk of plastic with a hole in the center. You can unscrew the shower head, remove the disk and drill a larger hole, perhaps 1/32 or 1/16 inch larger in diameter. If the shower head is crusted with minerals, you can soak it for a couple of hours in vinegar and scrub off the minerals with a toothbrush and clean the holes out with a piece of wire. You may also have bits of dirt clogging the shower valve, which can be taken apart and cleaned if you are handy.
You may want to do a flow check too. Open your hose bib fully and see how long it takes to fill a five gal bucket. You can compare the upstairs flow and pressure downstairs. Maybe some of the PEX got crimped? On a new house, I would want 3/4" lines to my bathrooms, especially if using some of the new shower technology.