Low flow shower - what's the next step?

[OHJason]

Hi all,

Hoping you can give me some advice on how to pursue this problem. Our house is only 3 years old and has a local city water supply. Over the past few months, the flow in our upstairs master shower has been going down.

Steps I've taken so far:
- Cleaned the showerhead thoroughly. It had lots of limescale build-up, but after cleaning the flow actually got worse once more of the openings on the head were flowing.
- Called plumber, they replaced the valve cartridge (Delta) and noted that they removed a lot of calcium build-up from there and in the shower arm. They said that the pressure to the valve was good, but even after cleaning and reconnecting, the flow through the showerhead wasn't any better.
- Their next suggestion was to replace the valve body itself, but that would involve tearing out drywall behind the shower in our bedroom and another $700...oh, and it still might not fix the problem.

So here are my questions:
1) Is limescale buildup to that degree normal for only 3 years?
2) Is there an alternative to replacing the valve, like a way to clean it
3) Is there any way to know if calcium build up in the valve body is the real issue? I really don't want to spend over $1000 and still have low flow.

Really appreciate any insight!!

 

[breplum]

What is the flow like with the shower head off?
What is the pressure at the house?
For further evaluation, check flow with the cartridge removed. This can take some fiddle-fix work to protect from water flowing back into wall and even more difficult if your valve body doesn't have integral stops.
If no stops, that is an indication of the dirt-cheap work of the installer.

 

[OHJason]

What is the flow like with the shower head off?
What is the pressure at the house?
For further evaluation, check flow with the cartridge removed. This can take some fiddle-fix work to protect from water flowing back into wall and even more difficult if your valve body doesn't have integral stops.
If no stops, that is an indication of the dirt-cheap work of the installer.

The flow with the showerhead off straight through the arm is low as well.
The pressure at the house is fine, I'm assuming, since we have good flow everywhere else in the house, including the other upstairs shower.
I don't know if they checked the flow with the cartridge removed, and I didn't know to ask them. I'm not sure about the integral stops either. That one is beyond my knowledge (which is why I'm here )

Thanks for the reply!

 

[GReynolds929]

Nobody in my area uses valves with stops on them. It has nothing to do with the quality of the installer or company. When I have come across them they usually don’t work from sitting unused for years anyways.

 

[Mitchell-DIY-Guy]

Just a guess here but is there a possibility of a shutoff somewhere between the first and second floor? I had such shutoffs located in the ceiling of my basement, serving the kitchen area of the home. Over time, the pressure on one of them (honestly cannot remember if it were hot or cold) began to diminish. As we had two sinks in that kitchen we saw it at both faucets. After cleaning and then replacing the aerators, etc. finally went into the basement. For some reason, somehow, one of the shutoffs (It was not a lever style) was half shut off, thus throttling the pressure to the kitchen. I went and ensured all these shutoffs were fully opened and problem went away. Shutoffs are always supposed to be accessible so if you have them they should be behind an access panel somewhere.

BTW, if you go through months and months of postings here, having low pressure/volume at a single fixture is fairly common.

 

[Twowaxhack]

Nobody in my area uses valves with stops on them. It has nothing to do with the quality of the installer or company. When I have come across them they usually don’t work from sitting unused for years anyways.

If he did have integral stops that would be a Suspected source of the trouble for me. One I would have to eliminate anyway.

We see them in apartments from the 70’s and on the European shower valves in the fancy pants part of town

 

[OHJason]

If he did have integral stops that would be a Suspected source of the trouble for me. One I would have to eliminate anyway.

We see them in apartments from the 70’s and on the European shower valves in the fancy pants part of town

There are no integral stops. They had to shut off water to the whole house to service it. All that's there is the valve, the two PEX lines coming in, and the PEX riser going up to the shower.

Just a guess here but is there a possibility of a shutoff somewhere between the first and second floor? I had such shutoffs located in the ceiling of my basement, serving the kitchen area of the home. Over time, the pressure on one of them (honestly cannot remember if it were hot or cold) began to diminish. As we had two sinks in that kitchen we saw it at both faucets. After cleaning and then replacing the aerators, etc. finally went into the basement. For some reason, somehow, one of the shutoffs (It was not a lever style) was half shut off, thus throttling the pressure to the kitchen. I went and ensured all these shutoffs were fully opened and the problem went away. Shutoffs are always supposed to be accessible so if you have them they should be behind an access panel somewhere.

BTW, if you go through months and months of postings here, having low pressure/volume at a single fixture is fairly common.

The plumbers told me that the pressure coming into the valve was great, but from the valve to the shower something is wrong. I guess what concerns me is that the pressure in this shower WAS fine, but has been diminishing over time. This leads me to believe that calcium build-up is a likely cause, but I was wondering if there are other things to rule out first and/or if there is a way to deal with the calcium without the headache of going through the drywall in the bedroom to replace the valve body.

Thanks for all the replies so far!!

 

[ReelPlumber]

Here's a thought. Do you know if the shower valve you have is a pressure balance type in the cartridge or the valve body? If the pressure balance part of the valve has the calcium build up it may be holding back the pressure. See if you can find a plumber in your area that can work on the pressure balance portion of the valve.

It may help if you can post a picture of your existing valve.

 

[Twowaxhack]

Here's a thought. Do you know if the shower valve you have is a pressure balance type in the cartridge or the valve body? If the pressure balance part of the valve has the calcium build up it may be holding back the pressure. See if you can find a plumber in your area that can work on the pressure balance portion of the valve.

It may help if you can post a picture of your existing valve.

It’s a Delta, and it’s just a few yrs old. So it’s a rp10000 rough valve.

 

[Twowaxhack]

There are no integral stops. They had to shut off water to the whole house to service it. All that's there is the valve, the two PEX lines coming in, and the PEX riser going up to the shower.


The plumbers told me that the pressure coming into the valve was great, but from the valve to the shower something is wrong. I guess what concerns me is that the pressure in this shower WAS fine, but has been diminishing over time. This leads me to believe that calcium build-up is a likely cause, but I was wondering if there are other things to rule out first and/or if there is a way to deal with the calcium without the headache of going through the drywall in the bedroom to replace the valve body.

Thanks for all the replies so far!!

Turn the water off, remove the cartridge and shower arm.

Install a 1/2” nipple and connect an blow high pressure air backward through the valve.

I use a high pressure nitrogen bottle at 250psi but air works too. Maybe you can blow some trash out.

If the cartridge hasn’t been replaced, replace it.

 

[OHJason]

Turn the water off, remove the cartridge and shower arm.

Install a 1/2” nipple and connect an blow high pressure air backward through the valve.

I use a high pressure nitrogen bottle at 250psi but air works too. Maybe you can blow some trash out.

If the cartridge hasn’t been replaced, replace it.

Thanks, I'll give this a try. Two questions -
- Can I get those supplies at a plumbing supply, I assume?
- Is it possible (or even worthwhile) to inject some CLR before trying the compressed air?

 

[Twowaxhack]

Don’t use any CLR. You really don’t need anything other than a way to connect the air compressor to a 1/2” nipple. You could leave the shower arm in place and just connect to that. It’s 1/2”.

 

[matt.mena]

I had someone call me to replace a kitchen faucet and, “Oh, by the way, can you see why we don’t have much pressure on the spare bath tub and shower?” Sure, why not.

House maybe 5-8 years old. I took the valve apart, cleaned everything, back together, same issue. Apart again, determined it was between the valve and spout with a pull handle for shower. I used a coat hanger and heard crunching inside the pipe and valve. There was crushed granite stuck inside the bend to the tub spout.

I crushed it more with a coat hanger till it all was small enough to come out. My guess is water main work done up the road introduced pieces of gravel or it was left inside a pipe from install.

A metal coat hanger fixed this pressure problem.