My son's new house has one bathroom where there is barely any water pressure. Essentially the shower is unusable. I looked in the basement and I think I found the pipes that supply the water (not yet 100% sure), and it looks like they may be 3/8.

If that's the case, that will mean a redo. Just making sure that 3/8 is NOT the norm?.

My understanding it that it need to be 1/2, usually coming off 3/4 "main" somewhere else?.


Also, there is a pressure gauge at the meter, and it reads 48 psi when there are no faucets running. Does this sound ok to you guys?. I thought it needed to be in the 50's. Someone told me MY house has 60 psi, and I have great pressure.

 

It's unlikely to have 3/8" piping. (not impossible though)

48psi static pressure (with no faucets on) is reasonable, low, but reasonable. The issue is more likely when a faucet is turned on, the pressure drops. This is often due to some kind of restriction in the pipes.

A few things to check
* Make sure all the valves are wide open.
* Are all the faucets the same and slow? Or just the shower?
* If it's just one fixture, it could be a clogged filter on the showehead or faucet

If the easy items aren't it, you mentioned a new house. Is it new new, or old, but new to him? When was it built?

 

Check the pressure gauge again with something running. If it lowers excessively.... that will be a problem for the second floor pressure.

Is it the shower only that has low pressure ?
I'm thinking possibly clogged shower head.

 

Hi, City Water or well water?
Woodbutcher

 

- a 1/4 inch copper pipe has a 3/8 inch O.D.

- a 3/8 inch copper pipe has a 1/2 inch O.D.

I think both of those sizes would be incorrect as a branch from the main trunk in the house to a fixture. I’m pretty sure those should be 1/2 inch – which would mean a 5/8 inch O.D pipe. Maybe the other guys know for sure.

 

It is just that one bathroom. Everything else is acceptable.....not great, but acceptable.

 

if you run the garden hose outside, the pressure drops to 42 psi. We will try a different shower head, but the sink also has just a trickle. It is only that one bathroom, though.

 

City water. There is a pressure pump installed but it looks like it is for the sprinkler system.

 

Mystery solved: the line in question was for a toilet, and the pressure problem was clogging, so PJMax wins the prize.