When it comes time to "winterize" (which is now), I drain all the tanks and open the low point drains. After all the water is drained I close the low point drains and I simply pull out my air comressor and "blow down" the entire system. I connect the air hose (regulated to 40 psi) to the city water connection utilizing an air chuck with a retainer to keep it on the valve stem. I then go through the RV opening each valve until I get nothing but air. I make the rounds three or four times to ensure I have all the water out. I also run the water pump for a minute or so to ensure no water remains in the pump. I then reopen the low point drains and leave them open till spring. I then pour some RV antifreeze down each drain to keep the "P Traps" from freezing. No issues with any seals or residual taste to the water.
