Is a backflow preventor valve required for a wet sprinkler system install in a residential dwelling?
No valve is required as long as you have a ‘flow -through’ type set up. This means that the piping that feeds the sprinkler heads must terminate at a plumbing fixture, such as a toilet. Ideally, that will ensure an adequate amount of fresh water flows through the sprinkler lines and prevent any stagnation of the system. The actual ‘drops’ to the sprinkler heads should be no more than 8 inches from the tee off the main that serves them. If this piping arrangement is not possible then a ‘testable’ backflow prevention valve must be installed at the branch where the line serving the heads takes off. A DCVA would suffice (double check valve assembly). Don’t forget to obtain a permit for this installation.
