Locating Water Pipes in House Walls?

CVC

My house is on solid slab and is 2 story with bathrooms upstairs. I need to locate where 3/4" water supply line(s) are located inside existing downstairs interior house walls, or at least roughly locating, before cutting into wall to specifically locate the line. Reason being that I need to run a new water line from this supply and code won't allow tapping to 1/2" lines. Can't do it from where the only known 3/4" line is at my water heater downstairs. The supply line I'm seeking would definitely be in a downstairs interior wall (not exterior) running upward to baths. Any suggestions on how to approach finding the line?

Thanks!

Just Bill

Better stud finders also have metal locating capability, as well as active wiring.

tpolk

i always used to find water lines with a nail or screw

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