Vacuum breakers (aka - backflow preventers) have always been one of those pesky Truth-In-Housing repairs for homeowners in Minneapolis and Bloomington, but those aren't the only cities where they're required. They're actually a requirement of the Minnesota State Plumbing Code, section 4715.2100 (D).
Cheap Vacuum Breakers Don't Meet Code
Part of the requirement for a vacuum breaker says any new device must be field testable. The minimum standard for a vacuum breaker meeting this requirement is ASSE 1052. Vacuum breakers that conform to this standard are about twice the size of the really cheap vacuum breakers that you'll find at most home improvement stores, and they cost about four times as much.
At left is a vacuum breaker conforming to ASSE 1052. You can see that it's about twice the size of the cheap vacuum breakers that conform to ASSE 1011, shown at right.
Cheap Vacuum Breakers Are Still Allowed...
So why do you see the cheap vacuum breakers all over the place in Minneapolis and Bloomington, and why are they allowed for Truth-In-Housing evaluations?
Minneapolis and Bloomington allow these because they don't want to place too large of a burden on homeowners. They want homeowners to be able to pick up a cheap vacuum breaker at the neighborhood hardware store for a couple bucks. They figure it's better than nothing.
...But Not On New Construction
If you look at any new construction home or at any sillcock that has been recently installed with a plumbing permit, you'll find the larger vacuum breaker, or the sillock will have an integral vacuum breaker. If the sillcock has an integral vacuum breaker, it doesn't need to be field testable.
The photo at left shows a standard sillcock with an integral vacuum breaker, and the photo at right shows a frost-free sillcock with an integral vacuum breaker. Both of these sillcocks meet the minimum requirements of the Minnesota State Plumbing Code.
Why Just Minneapolis and Bloomington?
So why is it that only Minneapolis Truth-In-Sale of Housing and Bloomington Time-Of-Sale evaluations require vacuum breakers? I suspect there has been too much complaining from residents in other cities. Even though this is the cheapest, easiest 'repair' item required in Minneapolis and Bloomington, I hear more complaints about this one item than anything else.
RELATED POST: Why Do I Need A Vacuum Breaker?
Reuben Saltzman, Structure Tech Home Inspections