Adam Preble wrote:
Awhile back I had asked where I might have a water shutoff on my
property. Looking at the hints, the only one I can find is the
municipal one undera manhole cover just off of my property. Of
course, the city doesn't want me to play with it. The only way for
me to do some plumbing improvements is to have the city shut it off,
and have them turn it on a few hours later--and hope everything is OK.

I don't like this idea and was thinking about the work required to
install a shutoff. It sounds like a PITA that isn't cheap to do.
Recently, I had thought about the work that goes into installing a
water softener, and I wonder if I could exploit that to add a
shutoff. I assume I could keep a water main shutoff inside the
garage this way, next to a water softener. It seems like the most
convenient way to go about it, but I wondered if there are some
perils in doing this.

Many softeners (I have a Culligan) have a bypass valve installed.
You just copper into the inlet and outlet lines.

Be aware that softeners must have air-gapped discharges. It
is against Code to run lines or hoses into ANY drain such
as your washer or a floor drain.