The Manabloc is a plumbing system used in many new homes. There are good and bad things about the Manabloc system lets start with the good things about the Manabloc.
The nice thing about the Manabloc is each plumbing fixture has a shutoff and if you have a plumbing emergency on a certain plumbing fixture such as a shower valve or a leaking hose bib you can shut it off and still leave the water on to your home.
The next thing is all your shutoff valves are located in one spot usually in the garage and is setup like a breaker box with all valves in a box some people think this is convenient.
Those are the pros; now the cons of the Manabloc.
Most of the older Manabloc systems are installed with polybutylene. This pipe has a history of failing and causing plumbing leaks.
The next thing is that the shutoff valves in the manabloc tend to leak if you never use them and when you do it is hard for your plumber to get parts for them.
I swear by the Manabloc Personally!