On Monday, August 10, 2020 at 9:11:16 AM UTC-4, dpb wrote:
On 8/9/2020 10:16 PM, Mike wrote:
My dad's house was built in 1978.

When my dad had to have a water heater replaced in 2016, the plumber
told him the water pressure was very high, at 115 psi, and he should
install a pressure regulator where the water supply comes into the
house, and that would be less stress on the appliances and faucets.Â* I
didn't know if the plumber was just trying to get more work or not.Â* The
water pressure has been 115 psi for as long as I know, with no problems..
I called the water department, and they told me yes it is 115 psi in his
location.

He likes the water pressure because the lawn sprinklers squirt far.Â* If
he puts in a pressure regulator, I see that they are adjustable,
generally up to 75 -80 psi.Â* That's a big drop from what he has now.

The all brass automatic sprinkler valves are starting to leak, and need
to be replaced.Â* Since they are next in line from the water supply
line/valve to the house, he thought that if he was going to replace the
sprinkler valves, which require removing the main valve to the house, he
might as well have the regulator installed too.

Will this big drop in pressure cause any of the seals/gaskets in
appliances/faucets which have been under 115 psi for years, cause the
seals/gaskets to 'back off' and not be held as tight anymore?

...

40-60 psi is considered a normal range; regulators generally are preset
at 50 psi.

Reducing the pressure won't cause leaks that weren't there before, no.

Outside pressure higher than inside wouldn't be a bad choice if you
could manage the arrangement conveniently.

--

+1

And IDK why replacing sprinkler system components requires turning off
the water from the street. The red valve shuts off all the water, the
blue valve for the sprinklers is after it. I guess since the main valve
is old, probably a good idea to change it anyway. Depending on the sprinkler
layout and range, reducing that pressure could be an issue or not.
But even there, if there is an issue, good chance you could have a higher
than normal system pressure, eg 75, but still have the sprinklers work
OK. On the other hand it's been high for a long time with no problems.
One issue could be that any new things added, eg refrigerator with ice
maker, may not be designed to handle it and they make all these things
cheaper than they used to, so it could be an issue with some new component
someday.