Bad water pressure getting worse

[Susanp]

Our water pressure has been poor despite replacing our well pump 4 years ago. The pressure leaving the Weltrol tank is good but it now takes upwards of 4 minutes for a toilet to recover from a flush and we can only run one thing at a time. I suspect our elderly Culligan water softener of causing the reduction in pressure, but we only saw a slight improvement when we put it on bypass for 5 minutes or so. (The house has a basement and 2 other levels. The 3rd level is the worst.)
I would appreciate suggestions, my well guy doesn't work inside and my plumber doesn't do well or old water softener stuff. We frequently have 50 or more people in the house so you can imagine the issues.

[Mike Swearingen]

What type of water supply pipes do you have? Galvanized? How old?
Mike

[Susanp]

What type of water supply pipes do you have? Galvanized? How old?
Mike

Between the well pump and the house I am not sure (this is 40+ years old). Once it comes in the house it appears to be a green PVC about 1 or 1.5 inches wide and this goes into the Weltrol. There is a ? 3/4" galvanized metal pipe coming out of the Weltrol and that goes into and out of our Culligan water softening system (which is about 20 25 years old (this has bypass valves to bypass this system). From there there is a 3/4 inch pipe supplies various parts and has a number of 1/2 inch pipes (presumably to the end fixture). The metal pipes appear to be either galvanized (which are original 43 years old) and some of the 1/2" pipes are copper which are about 8 years old.

The pressure valve on the Weltrol reads about 55, and goes down to about 43 when we open up utility sink faucets in the basement. The water stream weakens quite a bit even as the pressure reads 50. It took about 5-6 minutes to get to the 43 psi mark at which point the pump still has not kicked in. When we turned on the kitchen sink faucet, with the pressure between 43-45 psi, there is only a trickle of water.

[jadnashua]

You may need to budget for a whole house repipe. The galvanized pipe might be 3/4" on the outside, but sounds like it is likely only about 1/4" on the inside. The piping to the pressure switch is probably also nearly clogged shut, so it is hard for it to respond properly. You can have great pressure but you also need some volume; hard to get much through a soda straw. When all of the valves are closed, the pressure is normal, but it has no flow capability because of the size of the obstructed pipes. 40-years is probably at the end of its service life.