How to increase water pressure/flow in showerheads

Discussion in 'Shower & bathtub Forum & Blog' started by CindyJ, Feb 9, 2013.

  1. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    I have two brand new Grohe Movario shower heads in my shower. One is a handheld, the other is on a fixed shower arm. I'm really unhappy with the water pressure in both. Can any kind of adjustment be made to these shower heads to increase or unrestrict the pressure or water flow? These pricey components don't work as well as my old cheapo Waterpik showerhead. Thanks!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,948
    Location:
    New England
    For the most part, it's the federal requirements that restrict the max flow from a showerhead along with vanity faucets and low-flow toilets. Some of it is design, some is the available water pressure, and some of it could be the type of pipe used (cpvc and pex can't flow as much as copper, for example). Do you know what your water pressure actually is? Do you run both of them at the same time? Is either one or the other okay, but not when it's two together?

    Some of the designs have an easily removed flow restrictor, on some, if you're willing, you could drill out the inlet opening. But, for the most part, you may need to live with it. Fair warning, removing the restrictor will drain your WH quite fast!

    If your incoming water pressure is unusually low, and the supply is not restricted (just low utility pressure), you could add on a booster pump for the house...sort of like a small well system, but it's self-contained. This Olde House has one they did in their archives you could watch online to see what I'm talking about. Pretty simple to add. While many people live with incoming water pressure in the 20-40# range, 60# or so is nicer for things like showering.
  3. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    Thanks for your reply. There are a number of factors at work here. Last week we had the whole house repiped, changing from copper to CPVC. I wasn't aware that CPVC doesn't flow as much as copper. This week we had the new showerheads installed and now the difference in pressure is very noticeable. We have our own well and the pressure cycles between 40 and 60 PSI. I don't know whether it matters, but we also have a geothermal heat pump.

    I'm aware of the federal requirements with regard to water usage; still, I'd opt for modification of the flow restrictor if it would help. By the way, what is WH?
  4. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    And I forgot to mention -- only one showerhead can run at a time.
  5. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,053
    Location:
    North Vancouver, BC
    Often the new plumbing lines in a renovation or build are not flushed prior to hooking up the shower plumbing fixtures. This can lead to blockages and lower water pressure.

    I would first check the screens on the handheld hose for debris. You might find that there are three screens. I've seen plumbers remove a couple of these for added pressure. You need to be careful removing the restrictors in your plumbing items since you can give your drain more water than it can handle. I'd say 1 in 2 clients calls the plumber back to remove the restrictors.

    Many of my clients grew up with no restrictors and the new 2.5 Gallon per minute rule is not making grade.

    JW
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,932
    Location:
    NW Ontario, Canada
    Ask your plumber/heating contractor if it is viable to turn up the pressure. I located and removed the flow restriction in my new shower. I ruined a hand shower once trying to drill out the flow restriction. It was integrated into a swivel and drilling it out weakened it.

    Many modern shower valves have built-in flow limits to provide pressure balancing so there may be minimal gains to be had in removing restrictions downstream.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

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    3,932
    Location:
    NW Ontario, Canada
  8. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    My plumber just installed a Kohler K-304-K-NA Rite-Temp Pressure Balancing Valve. The back wall is still open so there's access to it if we need to get to it. Is there an adjustment that can be made to the pressure balancing valve that would improve the water pressure?
  9. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,932
    Location:
    NW Ontario, Canada
    The specs for that model say it has a 5.0 GPM flow rate. Most modern shower heads are 2.5 GPM. You could capture the flow into a bucket and calculate it, then remove the head and repeat the test. That will give you some indication of how much you might gain by defeating any flow restriction in the head. It is unlikely that you can change the flow characteristics in the valve.

    When I installed my shower, I tapped into the 3/4" copper lines going to and from the HWT. I also capped the shower side of the rough-in as it had a smaller port and used the tub filler side instead to supply the shower. I found and removed the flow restriction in the shower head. I am still limited by the flow limits of the pressure balance valve.

    Every change simply shifts the limit to somewhere else in the system. It eventually comes down to diminishing returns or expensive mitigations. I would consider raising the entire system pressure and add a CSV for constant pressure. In my case, the micronizer for my iron filter is the limiting factor preventing that. Changing that would be a major cost.
  10. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    I suspect the basic problem relates to your pipe replacement. Based on inside diameter, you need to upsize CPVC by one nominal size to equate to copper. In other words, replace 1/2" copper with 3/4 CPVC, replace 3/4 with 1", etc. 1/2" cpvc is too small for any but very short runs.
  11. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    I'm sure I never had a conversation with my plumber about the size of the CPVC relative to the size of the old copper piping. Maybe my husband did, but if so he never mentioned it to me. Is upsizing something that's done as a matter of routine? Do plumbers even know/care that it's necessary in order to maintain the water pressure? Now I'm really curious and I'll definitely find out.
  12. valveman

    valveman Moderator Staff Member

    Messages:
    4,428
    Location:
    Lubbock, Texas
    With a pressure switch turning the pump on at 40 and off at 60, shower pressure will never be very good. Installing a CSV could make the system maintain 55 PSI constant. That would seem like so much stronger pressure in the shower, that you almost no longer need soap (lol). Also if the pump is cycling on and off while the heat pump is running, as I am sure it is, you need a CSV to keep from burning up your pump/motor on a regular basis.
  13. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,932
    Location:
    NW Ontario, Canada
    Even with a CSV, I would consider raising the setpoints at least 10 or 20 PSI, so 50/70 or 60/80 if the pump has adequate reserve head.
  14. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    I may be getting closer to the source of the problem. The solution might not be so easy. My plumber's written quote for the re-pipe project states, "Supply and install new CPVC ½” and ¾” hot/cold domestic water lines." It doesn't specify where the 1/2" will be or where the 3/4" will be. However, further along in the quote it says, "Reconnect to ¾” supply to ground source heat pump with shut off valve." Maybe that means that the 3/4" was only to be used for the geothermal heat pump. What I do know, however, because the wall is still open and I can see what's printed on the CPVC piping, is that the water lines that come up from the basement to the showers on the second floor are 1/2".

    Now what do I do?
  15. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Just as an aside..... why did you replace copper with CPVC? Did no one suggest PEX? Why did you need to replace all the copper?
  16. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    How long or short is a "short run?"
  17. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    We had a deadly combination of low pH and copper piping, and after 35+ years, pinhole leaks developed. We had never had our water treated for low pH because we didn't know it was problematic. The first leak caused over $3,000 in damage. Since we had no way of knowing how extensive the leaking problem was, or where other leaks might (or already had) develop(ed), we decided to replace all of the piping.

    We did consider PEX, but (and this will probably sound like a copout) the repipe project was something my husband was handling, and for reasons I can't recall at the moment, the decision was made to go with CPVC.
  18. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    Given what I now know is a reduced flow owing to the replacement of copper piping with CPVC, would a CSV be safe to use with 1/2" CPVC?
  19. CindyJ

    CindyJ Member

    Messages:
    53
    Location:
    Pennsylvania
    ...and another question: We're about to replace all of the old toilets in the house with Toto Ultramax II. Will the reduction in water pressure affect the flushing capability of the new toilets?
  20. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    It will not matter, because all of the water used when flushing comes from the toilet's tank.
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