The mold issue is the big problem now. It's in the walls, behind the baseboard, and
most likely on the subfloor under the ceramic tile in the powder room and kitchen.
The moisture detector got readings through the tile. Most likely the tile and the
subfloor will need replacing. What a mess.
That may indicate a far more serious problem. You need to cut out that
section of pipe and see why it is leaking. You might find out there is
significant erosion of all of the pipe. That is somewhat unusual up
there where you have good water but people in the Cape around Wayne's
place have had a lot of serious pin holing problems in copper pipe.
The last I heard it was still in court with the plaintiffs fighting
about whether it was bad pipe, bad water or an electrical problem.
All of that made me a plastic pipe fan although there is some copper
in here that has been OK for 50 years.
The previous house we had up here was built in the late 1960's and we
had mucho problems with pin hole leaks developing in the copper piping.
Seems like every weekend I was down in the basement cutting out and
replacing a section or putting solder on a leak. I was told that in
the time period the house was built a lot of the copper piping was
coming from Japan and, for some reason, just about all the Japanese
copper developed pinhole leaks a few years down the line after
installation. We ended up replacing just about everything with new
copper. That was back in the late 70's. My daughter now lives in that
house (has for the past 15 years) and hasn't had any further problems
with leaks.
One benefit of copper over pvc in supply lines is that copper has
natural antimicrobial properties. If you are always running a lot of
water through PVC it probably doesn't matter much but long periods of
no use .. like in Wayne's case ... it could. Never liked the idea of
long, plastic tubing runs to a refrigerator's automatic ice maker
either. Not enough use.