ShowerHead and Body Jets Recommendations

I am building a new master bathroom, with multiple shower heads.

My first question is about pressure and GPM. I wanted to know what my existing system did. I got a pressure of 50 psi with only 2 gallons / minute. I was not 100% sure how to do the GPM test. I took a 5 gallon bucket and put it under the tub spout, ran cold water only and it took 145 seconds to fill. This does not seem enough pressure to make my system work. How many GPM with 1/2" piping and 50 psi pressure should I be getting?

I was planning on running new 3/4" CPVC piping to the shower. How many GPM should I get with 50 PSI under those conditions.

I want to make sure I will get enough to drive multiple shower heads. I was thinking of 4 body jets, a handheld and regular shower head. It would be nice to find a complete afforadable package. Does anyone have any suggestion on best value and showerhead recommendations.

Thanks in advance,
Robert

WHen it comes to good showerheads, you tend to get what you pay for. Did you get that flow through the showerhead or the tub spout? All showerheads sold today are flow restricted to be less than 2.5gpm. If you got that flow through the tub spout, you have other problems. If it was the showerhead, it may be normal. A typical 1/2" valve may flow in the order of 5-8gpm, depending on the temperature you select, and, some will flow less. A valve designed for high flow would be at least 3/4", and maybe larger, depending on the desired flow. Many 3/4" valves are not much better than a 1/2" one, but the higherst flow would be about 17-18 gpm.

That may all be secondary if you don't have a large enough water heater!

3/4" CPVC will flow the same volume approx. as 1/2" copper.... and that is in the range of 5 to 7 gpm.

Sadly, I took it at the tub spout, so must be other issues. I tried again at the outside faucet and got around 5GPM.
Copper piping in this city develops pinhole leaks, so people update to CPVC. If 3/4" CPVC will only flow at 5-7 GPM is that enough. If I had on 4 body jet and the overhead I would need more than that. I was going to take the lines from where they enter the hot water tank. At that point they are CPVC, but they flow back into the wall into what I believe is galvanized steel. I guess I could run copper and hope for no pin hole leaks over time. Or could I run 1" CPVC and then reduce down to 3/4" at the valve. What would you recommend.

Also you mentioned hot water. I am not sure how to calculate that. Lets say at most I had 4 body jets and the overhead on. That would be 10 GPM. But how much of that would be hot water???? I know it depends on how hot you set your water to and how hot your tank is, but just to get some idea. How big does my tank have to be for a 15 minute shower???? Maybe I only need 2 jets instead of 4. What size tank do most people with these systems have. I have a 60 gallon tank.

I have never been in a multi head shower before so I am not really sure how many jets are really practical and whether or not a rain shower head is a good idea or not.

Those pipes (pex and cpvc) have the same OD as copper, and because they are weaker than copper, the walls are thicker to maintain some strength, so the volume it can flow will be less.

If you really need lots of flow, you'll need copper all the way from your water meter to the valve in the shower or larger cpvc pipe.

If you have cpvc now in 1/2", it's equivalent to about a 3/8" copper pipe. Keeping in mind that the volume contains an r^2 factor, a small change in the radius makes a really significant difference in the available volume. The pressure would remain the same regardless of the pipe diameter, but the flow will be limited, appearing as lower pressure at the outlet if it can flow more than the supply. Think when you put your thumb over the end of a water hose...it goes further, not because the pressure goes up, but because you decrease the flow requirement - the pressure stays exactly the same. Same thing happens in a shower...have enough flow available, you're okay, require more volume, and you'll get a weaker output from all outlets.