Our house was built in 1986. The water pressure has decreased gradually. About 4 years ago we replaced the submerged pump (we have a well and septic). It didn't help the water pressure. I adjusted the pressure from the default 40 - 60 to 60 - 80. It helped but still seems too low. I'm afraid to raise it any higher. I don't believe the problem is the pump because three years ago we installed a sprinkling system that works great. When the sprinklers are on the inside water pressure does not seem to change. On the other hand if the first floor laundry washer is filling the upstairs shower is just a trickle. How high can I safely set the water pressure? Could the problem be the copper pipes are clogged? If so, is there a way to clean them?
I would guess that your sprinkler system has filters and/or a pressure reducing valve feeding it, which offers a substantial restriction so it affects things in the house less than a wide-open washer valve.
A 4 year gradual reduction in performance on a well system speaks to me of a failing, undersized or malajusted pressure tank far more than "clogged pipes." If you did not adjust the pressure tank pre-charge when you changed the system pressure, you would have aggravated that problem, and indeed, raising the system pressure without increasing pressure tank capacity (even if you did adjust the pre-charge) negatively impacts system performance, as the same tank has less tidal volume operating 60-80 rather than 40-60.
If you want to run the clogged pipe theory down, remove the aerators from all faucets that have them, remove the shower head, and (one at a time) blast as much water out each faucet or device as possible, perhaps collecting it in a bucket to see if there's any sediment to speak of. Generally if there is you'll see it before you get started, as there will be crud on the aerators, and cleaning those and the shower-head may help substantially. If you have hard water an acid soak may also help to remove calcium build-up/restrictions, which will be at those end points where water evaporates, not in the middle of the pipes.
A well with significant iron problems is one of the few cases where I've seen much of anything in the pipes, and a flush as described (and chlorine shock treatment, and more flushing) would remove that; even with such a build up it did not really affect flow significantly.
Now if your well is pumping sand or grit and you are not filtering it out, that could also build up to some extent, but again, you'd expect to see that at your aerators and to have a lot of valve problems from it, too.
If you don't have a problem with your sprinkler system and its performance, then I'd guess your well and pressure switch are ok.
- Do you have a whole-house water filter on your incoming line from the well (likely after your pressure tank and after your sprinkler system feed)? If so, make sure that has a clean filter in it. Our house is on a well and the whole-house filter starts reducing flow within a couple weeks of changing the filter.
- Does all your inside water get fed through a water softener? If so, it may have an internal obstruction that's limiting inside water flow. If all your inside water goes through the softener, there probably should be a bypass valve you can turn to see if that bypasses your problem.