I replaced the entire copper lines under my house a few years back with cpvc. The house was built in '73 and about 1978 they drilled an oil well about a mile away as the crow flies .In doing so they polluted all the deep wells in the area with hydrogen sulfide gas --skunk water .It ate out the lines .I called a well driller and sunk another well. Above the limestone at 117 feet ,no sulfer . The other well is 200,sulfer.
Now here's how geology works .I was using the sulfer well for my geothermal heat pump .Something happened ,the well appeared to "sand in" .I let it sit unpumped all summer then blew it out with a big air compressor and installed a super k sand trap .
The sand was blue clay slurry and evidently sealed off the aquafer that carried the sulfer,it's gone .