Most new construction in San Diego has backflow preventers on the water supply. We had to put one in for the companion unit. It is a big ugly thing. But it’s function is useful.
For the sewer line for the companion unit I know we have some kind of valve/backflow – but that may be integral with the pumps because it’s below the sewer line and has to pump the dirty water from a pump basin. Not typical at all.
Most places have a stormwater system, also. Would you have a backflow on that, also?
