I am trying to increase the water volume to my house. I currently have a 5/8 water meter to a 3/4 main that runs about 30 feet to the prv which ive replaced with a watts 223 and then goes to rinnai instant heaters. I cannot upsize the main or meter due to a $40000 charge by our local municipality to upsize the meter and they wont allow a 1" main hooked to a 5/8" meter. H2O pressure from the street is 125 psi. Do you think I could increase flow by increasing to 1 inch as the main enters the house upstream of the prv, then going with a watts 223 1 inch prv and 1 inch pipe to the rinnais, then i could plumb 1 inch pipes to the risers going upstairs. I am currently only able to get about 6-7 gpm out of our master shower and I plumbed 3/4 all the way to the drop ear elbows through a hansgrohe volume control and 3/4 thermo mixer, it just seems like we should be getting much more water flow. Also we got about 10gpm before the rinnais were installed and just had a 50 gal h2o water heater. I have 3 rinnais in parallel and with our ground water temp they should each make 4.5 - 5 gpm at 120 degrees. If I take the plumbing downstream of the rinnais out of the loop (hook up hoses to the rinnais and run them out to the street) then I can get the rated flows, but when I run the rinnais through the plumbing to the fixtures I cant get more than about 6 - 7 gpm, I definitely get alot more flow through the cold side. I know that the rinnais restrict flow but it seems like I should be able to get more flow to our shower. The prv is currently wide open. I changed the prv to the watts 223 because it was supposed to increase flow but I didn't notice any significant change. Also when they installed the rinnais they moved them to the far end of the basement which added about 60 feet of pipe and a bunch of elbows.