Which service line material is known to cause corrosion when connected to brass valves?

Galvanized iron is known to cause corrosion when connected to brass valves due to galvanic corrosion. This type of corrosion occurs when two different metals are in electrical contact with each other in a corrosive environment. In this case, the zinc coating on galvanized iron and the brass of the valve interact, leading to the deterioration of the galvanized iron over time.

The issue arises because brass contains a higher percentage of copper, and when in contact with zinc, a galvanic cell can be formed. This results in the zinc being sacrificed, which leads to corrosion of the galvanized surface and potential failure of the service line. Awareness of this compatibility issue is crucial for ensuring the longevity and reliability of the plumbing system.

The other materials listed do not present the same risk; for instance, PVC and polyethylene are non-metallic and do not participate in galvanic corrosion, while uncoated copper can corrode but does not lead to accelerated corrosion in connection with brass valves in the same manner as galvanized iron does.