Just when you though you had enough disclosures to deal with along comes Polybutylene plumbing.

http://www.polybutylene.com/poly.html

"Polybutylene is a form of plastic resin that was used extensively in the manufacture of water supply piping from 1978 until 1995. Due to the low cost of the material and ease of installation, polybutylene piping systems were viewed as "the pipe of the future" and were used as a substitute for traditional copper piping. It is most commonly found in the "Sun Belt" where residential construction was heavy through the 1980's and early-to-mid 90's, but it is also very common in the Mid Atlantic and Northwest Pacific states."

The problem with Polybutylene (or poly for short) plumbing is that some of it has a tendency to deteriorate and fail over a fairly short period of time. Not a good thing to happen to your plumbing, especially if it's inside interior walls.

http://www.polybutylene.com/realtor.html even has a section titled "Poly issues for real estate professionals".

Thankfully poly plumbing does not seem to have been used very much in my area so I only have to deal with it rarely.

There are some real horror stories about Poly pipes failing or developing multiple leaks causing damage running over $100,000.

The Polybutylene.com website advises buyers of homes with Poly plumbing to ask the seller to either replace the Poly or give them an allowance equal to the cost.

Estimates for replacing all Poly pipes seems to be in about the same price range as replacing carpet so while expensive, it's not cost prohibitive.

Personally I would much rather spend 5-10,000 now and replace this stuff rather than wait until it comes apart and spend $100,000 rebuilding my house.