Sunday, January 11, 2015

How to Thaw and Drain Waste Tanks

Well, the Winter Rving adventure continues in Our RV life.  Yesterday morning, it was 12 degrees.  And, our rinse & waste tanks were full.  So...time to dump.  But, wait!  We couldn't because the valves were frozen.  We have been using rock salt in the tanks to keep the liquids in the tanks from freezing.  But, in temperatures this low, that may not keep it completely thawed.  So, Chad came up with the idea to build a little foam board enclosure around the tanks that we can heat to thaw the valves / tanks as needed.  

How did we do this?

Items needed:

foam board insulation 

Measuring tape  

Knife / razor blade for cutting the foam

Duct tape 

First, you need to take measurements for the sizes you need to cut the foam.  We only wanted to enclose the area around the holding tanks.  
So, we cut two long pieces...... 

and two short pieces for the sides.  And, a few smaller pieces at the end to fill in the gaps.

The board is flexible enough to conform to the shape of the tire.

Tip - when cutting the foam it's easier to cut down the lines already in the foam board.

Chad cutting the foam board

The foam board configuration
Cut out the area for the sewer hose door.
We plugged our small electric heater into this outlet...

....which is located close by in the refrigerator vent compartment.

We placed the heater in the compartment.

The last step was to secure the corners and any loose sections with duct tape.

We left the heater running in the enclosed space for 5-6 hours.  The valves opened easily and the tanks drained with no problems.  Success!  


  1. God bless you if would find much easier to be where it is warmer, since your house has wheels it could move? This trick has been done by many to help with this issue for a while

    1. Yes, going south where it's warmer is ideal. We may be able to soon. But, for now, we will "tough" it out.

  2. This is a great idea. I wish I had an outlet like that right there in that spot! Maybe I can talk someone into putting one there for me, lol!

  3. Well,, that is actually the outlet that our fridge is plugged in to. But, our fridge is gas/electric, so we can run it off of gas while it is unplugged.