Copper Water Lines
Copper Water lines are found in most older homes and some newer homes. Copper water lines that are not insulated and left in unconditioned spaces can corrode over time. With corrosion the water lines can become damaged and small pin hole leaks can develop or even worse the pipe can weaken and become more suspectible to bursting. At unions with DIY fittings commonly available at hardware stores, dissimilar metals are sometimes used which can cause a galvanic response to occur, making the water lines suspectible to leaks.
These are some pictures from a recent inspection.