I havea sink in my garage. The concrete under the sink is saturated. I have checked the water line connections and drain/p-trap and they are okay. I cannot hear a leak behind the wall, so I don't think a pipe has burst. The sink is the last thing on the line after my washing machine, there is no water in the laundry room either.

You may have to open the wall, no magic balls here.

Dry the area and then lay stripes of toilet paper across the floor under the sink. The paper will quickly show you where the next water comes from, likely a leaking trap on your drain but you said you checked them, how did you check them?