Two valve manifolds far apart - one or two DCVAs?
As the pictures show, we have two valve manifolds on opposite sides of the house. The main water supply line is approximately in the middle of the two manifolds. I'm looking at two approaches for backflow prevention - one is to use a single DCVA near manifold A, with a connecting line running to manifold B; the other to install a separate DCVA near each manifold.
There's the obvious extra cost of the second DCVA and the additional fee for inspecting two rather than one DCVA. But it would be quite difficult to run a connecting line between the two manifolds - I have to route it through the crawlspace, through a semi finished basement, and through a finished room. So the two DCVA approach will be a lot easier to install.
Aside from complexity of running the pipe and cost, are there any other considerations I'm missing in deciding which way to go?