What type of plumbing concern is polybutylene considered to be?

Polybutylene piping is considered an outdated material primarily due to its history of failures and issues when used for plumbing systems. It was widely used in residential plumbing from the late 1970s to the mid-1990s. However, over time, it became evident that polybutylene is prone to deterioration and leakage, especially when exposed to certain chemicals or chlorine found in municipal water supplies.

The substantial number of leaks caused by polybutylene pipes led to significant financial repercussions for homeowners and prompted many insurance companies to refuse coverage for homes with such plumbing. As a result, replacement of this material became necessary, and many local building codes now prohibit its use. This context underlines why polybutylene is recognized as outdated in the plumbing industry today. The other options do not accurately reflect the state and perception of polybutylene in current plumbing practices.