How to quantify shower "pressure"?

[Theodore]

I’m in a private house, on a water well with a jet pump and bladder tank. The pressure gage on the jet pump shows me that the pump turns on at 40psi, and off at 60psi (with a little plus or minus each time). The bladder tank is less than 2years old. The main supply line from the bladder tank is 3/4" copper, and branches to 1/2” copper for each fixture. All copper piping is <10years old. Although I have hard and slightly acidic water, none of the 50year old copper pipes that I removed (in the past 10years) had any appreciable buildup within them. I have purchased but yet to install a water softener/acid neutralizer. The valves and valve assembly to the tub/shower were replaced this year, as was the tub's spigot with diverter to the shower head. The diverter/spigot works very well: leaks only a few drops when the shower is engaged.

All that being said, my shower isn’t as strong as we would like it to be and comparing to other showers (i.e. in hotels, on vacation, stays with relatives and friends, etc) makes us think there’s something wrong with our system. I realize that's a very subjective observation, so is there any *quantifiable* way to check our shower’s flow/pressure etc. and compare to (for example) a relative’s or friend’s house?

Putting a pressure gage on the shower head will only show me the static pressure, so that’s kind of useless. I’ve installed new/different shower heads but the result has been the same somewhat lackluster shower. I suppose it’s possible that I did a sloppy job at soldering a joint somewhere and there could be a partial restriction in the line, but how could I test for that? I’m only familiar with larger flow/residual pressure tests done on fire hydrants. Is there any objective test I can run on my shower and compare (apples-to-apples) to someone else or to a written standard? Just looking for some quantifiable way to check so that I can prove to the missus that, short of jacking up the 60psi setting on the pump cut off and increasing the risk of a leak in the walls somewhere, our plumbing is operating as it is supposed to.

Many thanks
Theodore.

 

[LLigetfa]

My guess is there is a flow restriction built into either the valve assy and/or the shower head. You can easily measure the GPM output by cataching the water in a bucket and timing it but reading the pressure just before the shower head would involve piping in a temporary Tee for a gauge. If the pressure drops considerably at the Tee, there is a restriction before it.

You could try adapting a pressure gauge to a faucet aerator to see if there is a pressure drop at a nearby fixture which would indicate a flow limit elsewhere in the plumbing or the pump. Pressure gauges are available with garden hose fittings and can be used at a washing machine hookup or other hosebib.

 

[Sponsor]

 

[Reach4]

To start, I suggest that you put a pressure gauge with a garden hose thread on the hot laundry supply connection or the water heater drain. That is cheap and easy. If you are seeing a large drop from what the gauge at the pump says while the shower is on, look for restrictions. For example, maybe you have a cartridge filter in line.

While thinking about pressures, I would put a boiler drain after the acid neutralizer and after the softener. These are useful for taking water samples, but they are also handy places to screw a pressure gauge to.

In addition to what LLigetfa pointed out, do you get much difference in flow for all cold, all hot, and warm? If you get more flow with warm, expect the problem to be drops in your piping. If similar, how is the tub flow? If the tub flows well, then the showerhead is the probable culprit.

Take the shower head off, and let water flow out of the arm. If that blasts, then you have confirmed the showerhead is your limiting factor.

 

[Jadnashua]

People confuse pressure and volume all of the time. A fire hose will have the same pressure as a soda straw fed from the same source, but the fire hose will deliver LOTS more volume.

Most tub/shower valves use a restrictor in the shower side verses the tub side and that's one thing, but, all modern shower heads are mandated to provide NGT 2.5gpm at a nominal pressure, so they have their own restrictor in them to limit that volume. If you can raise the pressure in your pump system, you will get slightly more volume of water through the shower head. FWIW, if you measure the volume you get out of the shower head, then unscrew that head and measure it again, as long as the volume with it removed is more than when it is installed, your shower head has enough volume. The design of shower heads will vary on the perceived pressure output. Take something like a rain shower head, and there's essentially no nozzle, and the water basically drizzles out. You need enough volume to produce a bit of back pressure on the supply line, then, the water flow speeds up to get through that restriction...otherwise, it just continues through without that amplification (caused by the Bernoulli effect). By adjusting the restriction and the number and size of the exit nozzles, you can adjust the 'feel' of the outlet spray. They have to balance that effect to abide by the NGT (not greater than) mandate of the 2.5gpm, though. Some people open up the restriction in the shower head (on some, it's an insert, easily removed), and others just drill out that restriction. But that will also have an effect on the amount of hot water you use and the length of a shower you can take before things cool off, and (in your case) the amount of water used and the cost of pumping it and heating it up.

Gone are the days of unrestricted showers, at least if you want to play by the environmental and social rules...lots of places have a water shortage.

 

[LLigetfa]

Most tub/shower valves use a restrictor in the shower side verses the tub side

Agreed, and easy to confirm if the restrictor in the valve produces less GPM out the shower arm with the head removed than out the tub spout.

I think they designed the restrictor for the anti-scald pressure balance spool to work well but then the shower head would have the same effect.

BTW, years ago I drilled out the flow restrictor on a shower head and it came apart. Turned out the flow restriction was a hollow rivet holding it together.

 

[Terry]

I would remove the shower head and see what comes out unrestricted.
New shower heads are all about 2 gallons a minute. I sometimes drill a hole in the restrictor to increase the flow. I just read the story above this. Funny. I haven't ruined one yet.