I have a tough question. House was built in 1960. Copper lines come up through the slab. 2 bathrooms on 1 floor both with showers. One shower works perfectly, no pressure problems. My problem... my hot water in the shower has low volume. Cold water has normal volume. I have a three valve shower. I have replaced the stems of all three recently. When I turn the hot water in shower AND the hot water in sink (same bathroom), the volume in the shower stays the same (low) and there is only a trickle in the sink. Cold water works normally. When the hot water in shower is on (full but low volume) you have hear the pressure buildup in the wall of the sink and can feel the water volume when you hold on to the hoses to the sink.
I have had 2 different plumbers come and tell me that the copper line has collapsed below my house. I do not agree. Of course, I not a plumber but it the line is pinched, why do I get varying volume in the sink? It runs normal volume hot and cold when shower is not on. And it does not make swirling noises during sink operation. Neither company will work on shower valves that are older than 30 years. So both want to just run a new line. Easier said than done. Water heater is in garage, hip roof with no room for skinny plumber and walls are plaster not drywall. One plumber wanted to hook up a compresser and blow the line (saying up to 200 psi) if it is a block but says he's "afraid" to do that and can't guaranteer it will fix the problem and doesn't want to blow other valves, please help!

Not sure I can properly imagine your layout.


2 bathrooms on 1 floor both with showers.

So you have two bath, each with shower, sink and toilet. Are these baths back to back, or in proximity to each other? Also what is the location relative to the kitchen? And what is there location relative to the garage where the water heater is. In other words, when the house was built, would the plumber have logically run a single 3/4" line to service all three?
I don't think a copper pipe would ever collapse, contrary to logic. It could get pinched but only if a broke and floor sunk or if a foundation wall it passes through sunk. Those things would have to be so significant that you would certainly know it.

I wouldn't go the high air pressure thing. He probably couldn't do it in the first place. It take something more than the portable compressor. If he did have a compressor that would create 200 lbs of pressure, he would have to do it with all the valves close then open the shower valve. If he did that he would probably blow a valve. They are just not designed to withstand that kind of pressure. If he did pressurize the line to 200 lbs and didn't blow a valve it wouldn't work any way. If there is a partial blockage you would just release the air through the blockage. If there is a pinched line the 200 lbs would not straighten the line out.


Water heater is in garage, hip roof with no room for skinny plumber and walls are plaster not drywall

Don't understand. What's the roof got to do with the water heater and pipe under the floor.

Post back and give us a better description of the layout.

Not sure I can properly imagine your layout.


So you have two bath, each with shower, sink and toilet. Are these baths back to back, or in close proximity to each other? Also what is the location relative to the kitchen? And what is there location relative to the garage where the water heater is. In other words, when the house was built, would the plumber have logically run a single 3/4" line to service all three?
I don't think a copper pipe would ever collapse, contrary to logic. It could get pinched but only if a broke and floor sunk or if a foundation wall it passes thru sunk. Those things would have to be so significant that you would certainly know it.

I wouldn't go the high air pressure thing. He probably couldn't do it in the first place. It take something more than the portable compressor. If he did have a compressor that would create 200 lbs of pressure, he would have to do it with all the valves close then open the shower valve. If he did that he would probably blow a valve. They are just not designed to withstand that kind of pressure. If he did pressurize the line to 200 lbs and didn't blow a valve it wouldn't work any way. If there is a partial blockage you would just release the air thru the blockage. If there is a pinched line the 200 lbs would not straighten the line out.



Don't understand. Whats the roof got to do with the water heater and pipe under the floor.

Post back and give us a better description of the layout.

First, thanks for taking my question. The layout is garage is first behind the garage is the kitchen (fourteen feet away from hot water heater). Behind the kitchen is the bathroom in question. Approximately 22 feet from water heater. And the 2nd batheroom is equal distance from hot water heater but on a different angle from it. Bathrooms are separated by a hallway. They are NOT back to back. I doubt all three are plumbed together.

I don't think there is a collapsed pipe. We do not have any obvious leaks and we still have the same water bill we've had for years.

I mentioned the roof line and such because instead of charging me a day's labor to investigate what the problem is... both companies just wanted to run a new line. In order to do that, they would have to run a line from the water heater out along the fascia board around the side of the house and back in. And in order to access the manifold (?) in the wall, they would go in from the backside of the bathroom which is a plaster wall. Guy says it would be a lot of work and what if it wasn't plumbed in the normal manner... he might have to tear out a "pretty big area"