"George" wrote
Yes, and they're found in smaller homes as well here. Oddly, our
insurance agent tells me that they don't reduce the cost of insurance,
since while they put out the fire, they cause flooding damage. One
offsets the other. I also have found that they are not automatically tied
to any alarm inside or outside of the house. It can be done, such as a
flow switch, but that's extra.

Considering the cost of sprinkler, the added cost of a flow switch is pocket
change.