What Are the Requirements for a Double-Check Back Flow Prevention Assembly?
A back flow prevention assembly box must be set back with a minimum of 12 of gravel below the bottom of the box (see Figure A). There must be a minimum clearance of 6 on each side of the double-check assembly and the box (see Figure B). From the handle tip of the double check gate valves, there must be a 3 clearance to both sides of the box (see Figure B).
