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If you are planning to purchase a home and wish to perform your own inspection, there are several potential plumbing problems to look for. One such problem concerns the use of less-than-desirable water pipe materials found in many homes built in the 20th century. Obsolete pipe materials can result in serious leaks and damage to the home or can even be harmful to occupant health. Below are three once-common water pipe materials and how you can identify them during an inspection:

Galvanized steel pipes

One common problem is the presence of galvanized steel water distribution pipes. For homes built before the 1970s, galvanized steel was a standard material in use for residential water pipes. Unfortunately, even though the steel is initially protected by its zinc coating, galvanized pipes only have a maximum lifespan of approximately 50 years. Eventually, the steel inside the pipe will begin rusting and will cause the interior space of pipes to fill up with debris from the corroded metal; in addition, leaks will develop when the corrosion works its way through the pipe. All of these problems will lead to the need to perform a costly re-piping of the home's interior water distribution system.

When inspecting a home for the presence of galvanized supply lines, keep in mind that some of the visible water pipes may have been replaced with a more modern material, such as PVC or copper. There may still exist galvanized steel pipes in the recesses of the home, behind walls or in crawl spaces. However, if you cannot access cramped or closed-off spaces to inspect pipes directly, you can still gather clues to determine if galvanized pipes are present. One such way to tell if galvanized steel pipes are present and corroding is to run hot water into a plugged sink basin. If the water appears cloudy or rusty, you can suspect that galvanized pipes are a likely cause of the problem. Another method of testing for the presence of galvanized steel pipes is to run all faucets inside the house. Low water pressure at faucets is a sign of corrosion-related debris accumulation inside the pipes.

Polybutylene piping

Along with the presence of galvanized steel pipe, another problem material used in home plumbing was polybutylene. This plastic was once commonly used for water distribution pipes, and literally millions of homes were built in the 70s, 80s and 90s with polybutylene plumbing. At the time, the material seemed to be a great advance in the industry and replaced the use of other obsolete materials. However, it was soon discovered that polybutylene is susceptible to becoming brittle due to exposure to water containing disinfectants, such as chlorine. As with galvanized pipe, pipes manufactured from polybutylene will require replacement before a leak develops.

To determine if a home contains polybutylene water pipes, you will need to recognize its appearance and markings. Polybutylene is designated with a stamp bearing "PB" somewhere along its sides, and it also will usually be gray in color. Fittings come in a variety of forms, but the use of copper elbows and bands is another clue the pipe is polybutylene. If you encounter polybutylene pipes during an inspection, inspect them for cracks and leaks at joints to help determine if immediate replacement will be needed.

Lead piping

A rare, but possible, material that can be found in some old residential plumbing is lead. Lead was commonly used to supply water to and inside homes up until the early 20th century, and though it has largely been replaced, you may still encounter lead pipes in old houses during inspection. Lead is now widely known to be a cause of brain problems and other serious health concerns, so its use as water supply lines inside a home is unacceptable.

Fortunately, it is fairly simple to determine if a pipe is made of lead. First of all, lead pipe is dull gray in color and is not magnetic, so just hold a magnet next to the pipe to see if it is drawn to the pipe. Second, lead is soft and can be easily marred or bent as a result. Inspect the pipe for gouging and scratching or for flat spots that indicate where it was struck or partially crushed. 

For more information and tips, it may be best to contact a professional plumber in your area.