Unfortunately galvanized steel pipe was used for both water supply and drain line piping in and around the Toledo area until the mid to late 1960’s, and in some cases well into the 1970’s. Galvanization is a process which plates or coats steel pipe with zinc in order to prevent corrosion, (oxidation). Because water flows on the inside of the pipe, over time corrosion still occurs but from the inside out.
As water supply lines age they become brittle and thin as a result of constant corrosion. During this same time the inside diameter of the pipe becomes smaller which causes low or lowered water flow. The
smaller the inner diameter of the pipe becomes the slower the flow of water is through that pipe. Some people also refer to this problem as low water pressure. The city water pressure coming into the house or the building is likely the same or higher than it was when the pipe was new, prior to the corrosion which occurred over tens of years. The problem is actually reduced flow (velocity) due to the clogging (oxidation) of the water supply lines.
Galvanized water supply piping may accumulate lead deposits over time and continue to serve as a lead source in drinking water long after all other sources of lead have been removed, including lead service lines and fixtures. These lines were used to connect the water main in the street to the building or home and in some cases the water main itself was lead.
Like galvanized water lines, galvanized drain lines also corrode from oxidation, specifically from added exposure to sewer gases which may include hydrogen sulfide, ammonia, methane, carbon dioxide, sulfur dioxide, and nitrogen oxides. Over a period of decades these factors contribute to the decay and corrosion of both galvanized steel pipe and even copper drain lines. Modernized plumbing systems use copper water supply lines and PVC or cast iron drain, waste, and vent piping, which are more durable and less susceptible to these problems, although there is no maintenance free solution, yet.