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Patrick, General Contractor
Category: Plumbing
Satisfied Customers: 2429
Experience:  30 years commercial construction and 23 years house remodeling projects
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Low water pressure in shower.

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Shower has almost no water pressure and all sinks are fine throughout the house. Couldn't shut off hot water one morning in the shower and removed stem to find part of the rubber washer and screw laying inside. Fished that out and replaced washers for hot and cold which fixed that problem. The pressure has been slowly getting weaker though over a long period of time and is now almost non-existent. Removed shower head and sprayed CLR in to clean diverter and problem still exists. Removed tub spicket, valve stems, and shower head one by one to turn water on and flush individually and problem still exists. HELP

Okay. Do you have good pressure to your bathtub spigot? When you removed your shower head, did you turn the water on and see what kind of pressure you had coming straight out of the shower pipe with no head on it? If you have pressure everywhere, you may just have a clogged up shower head. On a lot of low flow heads, sediment from your pipes, water heater and just from the city water supply, as well as hard water build up can block the shower head. If so, take the shower head apart and clean all the parts. I use a large needle to pick the grit out of the fine ports on my heads. Depending upon your shower head, screws are sometimes hidden under plastic caps. The removal of the screw allows you to break the shower head down. If you can get the schematics for your shower head, it makes it easier. After getting all the grit out, I soak the parts in vinegar or a lime dissolving solution. Be careful with yours so that you do not harm any finishes. I hope this helps.

Customer: replied 8 years ago.

Low water pressure from every orifice in the shower with all fixtures removed, even one by one, whether it's coming from shower with head removed, or tub spicket. While I had all of this out, I soaked the shower head in a bowl of CLR for a very long time also, but the pressure is the same with it installed or not.

Like I said, I even sprayed the CLR in through the shower pipe to clean diverter valve and nothing has changed. I was thinking that part of the missing rubber washer got stuck in the center of the diverter, so I also removed the tub spicket and ran a piece of .032 stainless safety wire with a hook on the end inside and found nothing.

I'm puzzled for what to do next because like I said there is pressure everywhere else in the house. Looked at plumbing behind tub and can't see any exterior damage to the pipes inside the wall. The plumbing does change from copper to that vinyl white tubing going up the wall to the attic, but still no exterior damage or kinks.

When you removed the individual stems, etc. to flush everything, did you have good water pressure? What make, model and manufacturer is your shower/tub valve?

Customer: replied 8 years ago.

Prior to the water not shutting off the water pressure was better, but still not good like it should be. Like I said, it was great when I first bought the place 4 years ago, but has gotten worse in the past few months. After the hot water wouldn't shut off about two mornings ago, and I had to pull the stem to find the screw and rubber washer laying inside, which is why it wouldn't shut off. All that was left of the washer was about the size of the screw head, but was swollen, so the outer portion of the washer is missing. I installed a new washer and that fixed the problem with the shut off. After the repair is when the pressure became almost non-existent. This is why I'm thinking the missing portion of the washer could possibly be what is clogging the center of the diverter.

I know the fixtures are something common that starts with a P, can't remember what they said it was at Home Depot...Puritan or something. The guy said that they were very common though.

I have access to the back where the pipes are through a cut out in the next room. I guess I'm planning on investigating the attic first to see if I might have a pinched or kinked vinyl tubing or something. At that point if I don't find anything obvious, I guess I will desolder the diverter, attach a piece of tubing to run to the tub, and turn water on to check pressure. If I have good pressure, I guess I'll be replacing the diverter if I can't get it cleaned out.

Does it sound like I'm on track? Believe me removing and replacing that diverter is the last thing I want to have to do. Been a few years since I've soldered copper, but I was pretty fair at it. Just kinda a tight space to be working. If you have any other ideas I am open to try anything before that.

OK. Check out the attached site and look at the diagram. I believe this is your situation, please verify. I believe your next step should be to remove the diverter valve and clean it out. I have a good suspicion that your rubber washer broke apart and when you replaced it it just shoved it down the faucet farther. Take the diverter out and try fishing straight back in. I would get a flashlight and try to look down into the valve body as best you can to see if you can see a blockage. If you had access to compressed air that could be a good way to blow it ou. Remove the shower head and the spigot and allow the open pipe to let whatever is blocking out. At least, this would let you know if all is clear.
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Customer: replied 8 years ago.

Thanks for your help. I ended up cutting a hole in the shower wall and replacing the diverter and installing a whole new fixture kit. Patched a hole with that water proof board you buy at Home Depot and caulked it over the hole.

Got water pressure now! Tried blowing it out first and it didn't work. Took me all Saturday, but I got it finished. I used those new shark bite fittings made this a fairly simple job. I never could get the diverter desoldered.

Again, thanks for your help.

Low water pressure in shower troubleshooting 

If all your neighbors have low water pressure, this could be an issue that needs to be fixed by the water company. If that is not the case, there could be a problem with the valves and pipes. In homes older than 20 years, steel pipes were often used and may have become backed up with lime deposits that interfere with the water flow. To solve this issue, contact a plumber. Before doing so, follow the troubleshooting tips below to try and resolve low water pressure.

Shower head


Low pressure in just one fixture – First check the flow restriction and see if there is a washer stuck, clogged aerator or if there is a closed supply stop valve. If the fixture has an aerator, check that first and see if it needs to be replaced or just cleaned.

A shower head may have low pressure due to a restrictor. If this is the case, remove the restrictor (rubber or brass disk) or a washer that has become stuck.

Low water pressure throughout the houseLocate the water meter outside. There is typically a shutoff valve (often on both sides of the meter). Make sure these valves are open completely by turning it counterclockwise. If the valve is partly closed, opening them up should help solve the issue.

In some homes, the main supply valve is near the cold-water pipe. After finding the cold-water pipe, turn the valve counterclockwise to open it fully. If the house has a water-pressure regulator, this is typically by the main supply valve. This issue may need to be corrected, which is usually done by a plumber or someone with experience.