Polybutylene pipe was installed heavily in the 1980s and 1990s in residential water distribution systems. They were cheaper to manufacture than copper, and they were also easier to install. This made them much cheaper overall than the tradition copper tubing that was used in many plumbing systems of the day. Well, the problem is that the polybutylene can become fragile if stressed by bending or temperature fluctuations.
Also many of the fittings used in polybutylene systems turned out to be a defective design! This caused major problems with leaks and water damage in homes, and most builders and plumbers stopped using polybutylene pipes back in the 1990s.
There are basically two types of leak problems with the polybutylene pipe systems.
1) Polybutylene pipes can become fragile over time.
One way for this to happen is when installed under stress and overly bent. Polybutylene pipe can become weak over time when it is bent and many installers just didnt do a very good job during the installation of these pipes.
Another problem seems to be temperature fluctuations. When these polybutylene pipes are exposed to freezing cold in a gusty attic, or they become overly hot from excessively heated water flowing through them, they become fragile over time. I remember working on a mobile home that had polybutylene pipes, and I had to make multiple trips out there over the years and it was always on the hot water piping. The homeowners could not afford to repipe all the pipes and so they just had me do the repairs as needed. My plumbing company ended up replacing virtually all the hot water piping with new PEX (cross-linked polyethylene) piping over a few years time.
The water heater thermostats had been turned up excessively, and the piping was semi-exposed underneath the trailer. The combination of extremely hot water flowing through the piping, and the gusty cold wind that blew under the mobile home made the hot water pipes become brittle and crack!
Also, certain chemicals in the tap water, such as chlorine, can cause the polybutylene pipe to break own over time.
2) The plastic polybutylene fittings can crack.
Although I have seen the metallic fitting leak on polybutylene systems, the most problems seem to come from the discontinued poly fittings, which were way to brittle in my opinion, and caused all kinds of property damage over the last couple of decades due to leaking.
Most plumbers who come out to repipe your home will use the new PEX piping and fittings to repair or repipe the old polybutylene. Unlike polybutylene, PEX (cross-linked polyethylene) piping is much stronger and is far more resistant to stress, temperature and chemicals. To make the repair, there must be some kind of transition fitting used. Either a PEX to poly barbed brass adapter, with copper crimp rings, or a push-fit type of fitting such as the Sharkbite connection fittings. To use the barbed fittings, you will need to buy an expensive crimping tool, so if you want to do this repair yourself, it would be cheaper to just buy the push-fit fittings, such as Sharkbite.
The repairs are fairly easy, if you have the right tools. But if you have multiple leaks, it is probably wise to contact a professional plumbing company that specializes in polybutylene replacement and getting some estimates to have the entire system replaced.
I would like to say for sure that cost of replacing your polybutylene pipes will or will not be very expensive, but the truth is that it really depends on many different factors and which plumbing company does the estimate. Not all homes are plumbed equally, and not all plumbers use the same technique, or charge the same. The best advice regarding the cost of replacing your polybutylene plumbing system is to get several estimates from licensed plumbing contractors.
You may have heard that there is a class-action lawsuit associated with this polybutylene pipe and fittings. It is probably too late to make a claim, but for detailed legal information on the lawsuit you can check this website: http://www.spencerclass.com/