How To Identify Polybutylene

Polybutylene is a type of plastic commonly used in plumbing pipes during the 1970s up to the 1990s, until it was discovered they deteriorated from exposure to oxidants in processed water. Before you purchase an old house, you must identify if the pipes within are polybutylene in nature; otherwise, you can spend a lot in replacing them and fixing damage if the pipes dissolve.

Here are tips for identifying polybutylene:

  • Check out the color. Blue, black, white and metallic gray were common colors for half-inch to one-inch polybutylene pipes. Blue polybutylene is predominantly used outdoors for transfer of cold water. Do not mistake black polybutylene with the more flexible polyethylene pipes, which has a better performance record. Do not also mistake white polybutylene with PVC pipes, which are known for their reliability. Metallic pipes are obviously not polybutylene in nature.
  • Inspect the markings on the pipes. Polybutylene are printed with "PB" by the manufacturer as ready reference for contractors and repairmen. They are also followed by a series of numbers. For example, a common marking is "PB2110". Polyethylene pipes are printed with “PE”.
  • Examine the flexibility. Unlike rigid pipes made from copper and other metals, polybutylene is flexible and may curve as it stretches out between fittings. Polyethylene pipes are more flexible and can be easily coiled, as a result.
  • Limit your search to likely areas. Polybutylene was used only for potable water, so skip the inspection on waste or draining pipes. It is located near the water heater for the house and extends out of walls to connect with sinks and toilets. Outside the house, polybutylene pipes are found entering the house through the basement wall, by the water meter and at the primary water shut-off valve.
  • Be ready to expose the plumbing inside bathrooms and sinks. Polybutylene may be hidden under tiles and panels in toilets and showers, so you need to remove these obstructions to check on the pipes. Keep the sampling area to a minimum to reduce damage to the room.
  • Keep an eye out for brass, copper or aluminum crimp fittings. These types of fittings were commonly used to fasten polybutylene pipes to plumbing joints.
  • Avoid inspecting for damage or deterioration. Polybutylene flaking occurs within the pipe and is not apparent at the exterior. Deterioration cannot be evaluated unless the water is shut off and the plumbing disassembled, a complicated process that goes beyond the scope of most home inspections.
  • Consider hiring a house inspector. An inspector has the experience to evaluate a house for value, condition and need for repairs. Not only will he identify polybutylene pipes, but other subtle signs of damage or problem areas. With his detailed observations, you can ask for a lower price on the place or a pipe replacement prior to purchase.

Take note that a lot of insurance companies won't cover a house if it's found out that polybutylene pipes are used in its construction. Have a house inspected first prior to purchase, or you may be stuck with a home that won't be insured.


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