Combining gray and black water

[liftinglarge]

We just bought a Myacht 3510. It only has a black tank. gray water is drained into the lake. In NM this is not legal. I wanted to plumb the gray lines into the black tank. Has anyone done this? Any issues?

 

[harringtondav]

First thing that comes to mind is to collect all gray water in a bilge container with a float bilge pump into the black water tank. Many boats use this type of system to lift shower waste overboard. Connecting into the black water tank will take some work unless a second fitting is provided. One gray water hose will be easier than several.
Anti back flow check valve on the gray water lift line is a must.

 

[Scott Danforth]

your local marina probably has done this many times.