Often times when conducting a home inspection with a buyer, we comes across grey colored supply pipes, verses the white shiny pipes (polyvinylchloride.) Most buyers are completely oblivious to any difference and would not know the potential problems associated with the polybutylene (grey colored) water lines. So, here’s a short primer for your consideration.
Back in the early 80’s when copper pipes were used, a newer more cost efficient water line was developed. At the time it was thought to be the greatest thing since sliced bread by building trade contractors. It was more cost effective and installation was made easier than the traditional copper tubing. The new product was made of polybutylene resin. Identifying this type of water supply line is fairly easy; generally a dull finish grey inside a residence and often time black or blue if used outside.
So, what has happened to make this water piping so damaging? It appears by all research the chlorine in water, extensive sunlight, and other chemical residues in water, can etch and create lengthwise hairline cracks in the pipes over time and erode the pipe from the inside out. Now you can well imagine a crack in a water pipe when applied under water pressure, can (and most assuredly will) create a household disaster. These water pipes can break down over time and cause very damaging water leaks. Although at the time polybutylene pipes were introduced it was building code approved- no longer.
When buying a home, my suggestion would be to ask the seller to replace or give you an allowance to replace these water pipes. Don’t let the seller convince you they are fine and will never leak. It’s really not a matter of if they will leak, it’s a matter of when they will leak.
Here is a couple fairly authoritative articles for your review: