Water Supply Line Inspection
The most common type of water supply piping is copper piping. This piping is used to supply water service from the municipal street connection to the dwelling, as well as from the dwelling to the interior of the house. It's important that copper piping not be kinked as this will drastically reduce water flow. Residential service piping is typically 3/4 inch diameter. Larger homes may have 1 inch or greater. The horizontal supply piping within the structure is generally 3/4 inch with 1/2-inch risers to plumbing fixtures (sink, toilet, etc). Smaller homes or homes with one bathroom may have 1/2-inch supply piping.
Copper has long been a very dependable material. However, if the home is supplied by a well and the water is acidic or has a low pH level, it will tend to eventually corrode and degrade the copper. Subsequently, when the walls of the pipe wear thin, the failures will look like tiny, round, green patina stains. If these stains are ignored, water may spray through the hole in the center of the round stain. This problem, generally due to the acidic water, can be neutralized with a mechanical water softener or filter.
Water hammer, otherwise referred to as the banging noises heard when water flow is abruptly stopped, is not unusual in metal pipe configurations, such as copper or steel. The momentum of the water flow stoppage makes the noise. One solution is to provide an air cushion or shock absorber that will soften the movement or momentum of the water. Some water supply systems have air tubes or diaphragm appliances installed in the piping system to prevent hammering.
Polybutylene Piping (PB)
Polybutylene piping is flexible, gray, plastic piping with epoxy secured joints, or inserted fittings and metal crimp rings. This material has been known to be defective at the junctions. Barbed brass or copper insert fittings with crimp ring joints are generally more dependable than the epoxy joints. The joints are vulnerable to chlorine in the water, which causes deterioration. The insert fittings have been in use since 1978 and may still in use today. However, production and installation pretty much ceased after 1995.
Most municipalities do not allow certain types of PB piping to be used for residential potable water because of their potential for leaking. There have been individual, as well as class action lawsuits, concerning certain manufacturers of this product.
The major manufacturers of PB piping were Quest and Vangard. Since they can no longer purchase the resins necessary to produce this material, they have switched to production of PEX. This is is a type of Polybutylene that is acceptable for potable water use in most areas.
A second type of polybutylene piping is “Big Blue". This piping is typically utilized in the main water service to the house. Its name was derived from the color of the material. The material is 1 1/2 to 2 inches in diameter and was rated for cold-water installation only. The major problems that surfaced with this type of PB piping are related to poor installation practices.
Galvanized Steel Water Service and Supply Piping
Galvanized steel piping is still in use, however, not installed any longer in modern construction. It oxidizes from the inside out. The oxidation (rust) reduces the interior diameter of the pipe, restricting the flow of water, and usually begins leaking at threaded joints where the pipes are joined. This is analogous to hardening of the arteries in humans. Adequate water supply can normally be restored, to some extent, by replacing the horizontal supply piping in the basement (assuming they are accessible) with copper. Replacing the vertical risers in the walls is much more difficult and expensive than accessible horizontal piping. Replacing all of the older galvanized steel piping would be the most desirable solution, but also the most expensive.
If the supply piping from the municipal water lines is galvanized steel, it is likely that the service piping is also galvanized steel. Galvanized steel piping fails sooner at the heavier used fixtures (i.e. the kitchen sink and the main bathroom). Failures are usually related to the amount of oxygen that is present. The more a fixture is used, the more water (and oxygen) is present, which corrodes/oxidizes the piping at a greater rate.
First clues of failure in the piping are roundish rust growths, commonly called rust warts, on the outside of the pipe. These are failures that have come through the pipe. It is not unusual for the corrosion to seal the failure temporarily.
Polyvinyl Chloride Piping (PVC)
PVC piping is approved for cold water only. Chlorinated polyvinyl chloride (CPVC) is approved for cold water and may be used for hot water, but not over 140° Fahrenheit. PVCs are joined with a primer and solvent cement. PVC piping is not a conductor and cannot be used for an electrical ground.
Polyethylene Pipe (PE)
Polyethylene piping is typically used as service piping. Generally black in color, it is a flexible material that is easier to install than most other service pipings. Joints in PE piping may not be made with adhesives or solvent cements. Joints should have two stainless steel band clamps, but the connection to metal (such as copper) is typically made with one clamp. The fittings have a smaller interior diameter than the piping. Therefore, PE must be sized based upon the fittings. This material is approved for cold water installation only and is very often found in well water applications.
There is very little lead supply piping in use, however, you may see some lead service piping in 80+ old construction, urban or rural. The prominent concern is the probable 6-inch to 8-inch municipal main in the street that is also lead. Historically, only trace elements of lead are measurable in residential domestic water systems.
Threaded brass is uncommon, however, you may still see it in homes built before 1940. The same things that affect copper tend to impact brass.