Keeping our external water tank thawed over winter (tutorial)

Dear Northern Alberta,

We’ve had enough with your shenanigans! This winter we WILL defeat you. Not again will our water freeze leaving us helpless in the middle of a frozen wasteland. We will be victorious!


The Copper House and Allies

How do you keep your water thawed during winter?

I have been asked this questions a lot. I  have also asked this question countless times with little to any feedback. In our first year living tiny I did not encounter anyone else storing water outside the home (above ground) and living in a freezing climate. The following blog post addresses a play by play of everything we are doing to keep our gigantic outdoor water tank happy and warm all winter long!  So, without further ado, here it is!


Meet our tank! This 1000 L water caged behemoth sits outside our home and provides us with all of our water. The tank was purchased on a classifieds website for around $200. To fill the tank we visit a local water fill station with a truck and load up a second tank. We then run the water from the back of the truck into our ground tank to fill it.

1000 L metal cage tank
This is Mike. He is our friend. He does great things and has wonderful ideas.

Note: If you are purchasing a pre owned water tank,  ask what was used for prior to sale. Many of the cheaper tanks have been used for chemicals. You can consult the label or the phone number to check the tanks history. Some factories steam clean their tanks multiple times before sale and may market them as potable.  Also, be aware that even with a new tank, the plastic taste can leak into drinking water. 

We had a few ideas of what we wanted but not a master plan.We knew that we wanted to encapsulate our water tank with a structure made from sustainable goods. We choose straw because of it’s high insulation value, biodegradable properties, fire resistance and affordability. It was also important that one of the interior walls from this structure was the side of our house. This way we could harness the radiant heat from our home and use it to our advantage in keeping the structure warm.

Our friend Mike, who builds homes for a living, met with us to brainstorm. He brought some wonderful ideas to the table. One of the most interesting ones was the use of geothermal heat from the earth. He suggested digging multiple 8 foot long holes into the ground beneath the water tank. The heat from the earth would rise up into our structure ensuring the tank remained warm.

My main goal has to been avoid the use of electrical when heating the tank. Any appliance that outputs heat is going to dramatically drain power which is a problem for anyone relying on solar. That being said, we really can’t allow our tank to freeze again this winter. I finally gave in and agreed to embrace a submersible water heater coupled with the use of electrical heat tape. Having it in place would at least serve as a wonderful backup plan if the temperature of the water was to drop dangerously low this winter.

The use of a submersible heater presented another problem: How were we going to fit the heater into the tank? The opening of the tank was much too small! I traced the submersible heater and drew cut lines onto the tank with a permanent marker. Next, I drilled 8 narrow holes, 4 onto each side of my cut line. With a dremel, I cut the opening and dropped the heater into the tank. I then passed zip ties through the holes I drilled and tightened the plastic back into place. Lastly, I sealed the opening closed with silicone.

  Submersable heater Dremel and opening Silicone application

When the day came, Mike showed up with a manual auger. First, a large hole was shoveled into the ground that our water tank would slide snugly into. Next, Ryan and Mike dug and dug (and dug and dug) three 6-8 feet deep holes. They also gained 5 pounds in muscle each. Thanks you two!

Holes being dug Augered holes

Next, we set to work on the base for our enclosure. We purchased some treated lumber and cut it to the dimensions we needed. Connecting them was labor intensive. We predrilled holes and then hammered 12″ nails into place, resulting in a very sturdy base.

Holes drilled Nails hammered Base

The very next weekend we were hit with lots of snow which was about a month early. Working in the slush and moisture is not ideal but we went ahead anyways. Lesson learned…don’t leave important projects until last minute. Once the base was in place we lined it with stones so that the straw walls would be able to breath. The first layer was larger rocks and the second was smaller ones.

My fantastic father-in-law showed up on this very same weekend and helped out. He set to work utilizing his cabinet making and contractor skills. We began drilling 2X4’s into place, making slots to slide in the straw bales.

Rock lining Base with walls

Working with bales is quite easy. By drilling holes through a narrow piece of wood, I was able to create a threading tool. To pair down the bales, I hammered the threading tool through the bale and retied the twine. We formed several one and two foot bales to work with.

Bales threaded Hammering through bale Small bales

The bales were shaved down with a jigsaw or by hand so that they fit firmly into place. We cut down some bamboo gardening supports (because that was all we could find late in the season) and drove them through the straw bales. We chose to use bamboo instead of rebar because metal attracts moisture and we did not want to draw liquid into the center of our walls.

Pressing the walls Straw bale walls

Mike donated a roll of Tyvek to our project. Tyvek was a great choice for protecting our walls because it is water resistant, light weight and breathable. We stapled Tyvek into place around the structure and fixed the wrap directly to the exterior walls of our house where ever it made contact. Finally, we sealed the top of the structure with two insulated tarps. Tarps may not seem like a fancy solution, but they offered us accessibility. Because this is our first year with this structure, we decided it would be best to have peace of mind that if our tank is to freeze we could easily disassemble the structure and have access to the top of our water tank. This way we could break apart ice if it was to form in our water tank or swap out the submersible heater.

Straw bales in place Tyvek wrap Revealed opening

Last but not least, Ryan designed a door. He decided it would be best to create a “cork” that would slide in and out of place. My father in law suggested this because would offer more square footage to insulate than a swinging door. With rope, anchors, spray insulation, and standard house insulation he created this beauty:

Door cork Door cork handles Door cork

And voila! That’s it for our water structure. We have been monitoring the air temperature and with the heaters turned off and it has remained surprisingly warm inside. I will follow up with another blog post in a few months detailing temperature readings and additional feedback about how our build is holding up.

This was a very thrown together project! If you have any suggestions or questions please don’t hesitate to comment below.


5 thoughts on “Keeping our external water tank thawed over winter (tutorial)

  1. […] Click here to see our current water tank structure (November 2016) […]...
  2. Eddy Winko Reply

    Great idea, hope it works. How low do the temps get in the winter?

    1. livingtinycanada Reply

      We will let you know when we get into our coldest months!

  3. JC Reply

    Interesting solution. One idea that occurred to me ehile reading this is it might help to wrap the tank in black tarp to draw in the suns energy.

    1. livingtinycanada Reply

      That’s a great idea! I’ve also heard that can reduce algae growth within the tank, though that hasn’t been a problem.

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