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Passionate experience junkie. Lover of the arts and architecture. Want to see and share the world, one village at a time.

How an Algebraic Equation Saved Our Hides

House sitting and immersion travel in Europe

Josie and Conrad

You know the math you took in school and said you’d never use? Well that’s how I felt about those classes, but Conrad retained the algebra, calculus, geometry and physics lessons. And we’re both glad he did. Here’s what happened:

Conrad and I accepted a two month house sitting assignment in Southern Spain for an off-the-grid mountainside adobe cabin. We were excited for the challenge despite our ages – I was 56 and Conrad was 70. House sitting around the world had been such a rewarding and life-changing way to travel so we felt ready for this remote adventure.

In Skyped conversations with the homeowner prior to arriving in Spain we learned about the water system there. On those scrubby mountainsides, water is scarce, but an underground reservoir serviced several homes on the mountain. A series of pipes ran down from the reservoir with each home accessing the pipes into holding tanks. We were required to adhere to a very strict schedule so each home received their monthly share of water.

Remote house sitting and immersion travel in Europe

The water valve was buried for security

Here’s how it worked:

  • On a set day each month, we switched on our water valve
  • The water filled our holding tanks
  • A few days later, another mountain home turned on their water, which turned ours off
  • The water in our tanks must last for the month
House sitting and immersion travel in Spain

Inside our mountain home

So we settled in to a routine there and overall had a memorable house sit, but not every day on the mountain was heavenly. Our time was marked with deep challenges. The biggest was when we discovered one of the two cylindrical water holding tanks had a leak. The precious water was seeping out and there was no way to stop it. The remaining water had to last us until the next month when we could fill the tanks again. The only answer was to ration what we had left. But how do we know what we used each day?

House sitting and immersion travel in Spain

A steep climb and we were at the holding tanks

That is where the algebra came in. Here’s the formula for the volume of a cylinder:


V= πr^(2 ) h


Conrad used the equation to determine:

  • How large the tanks were
  • How much we were losing each day
  • How much water we could use each day in order to have the water last out the month

These were the answers:

  • We could only use 25 liters of water each day
  • The World Health Organization determined that 60 – 80 liters  is a healthy allotment of water per human per day


Now before I make us out as some wilderness survivors, we did find a resource for water in town. There was a manual pump – you know the kind where you pump the handle up and down to bring the water out the spigot – a few miles away, so we drove there each week with containers we found around the house. We used that water for drinking and cooking which was actually very convenient because our piped-in mountain water had to be boiled first.

But we still needed water. So here are the changes we implemented in order to keep to our ration of 25 liters a day:

  1. Four cups of water only for washing dishes. It can be done and I got pretty darn good at it.
  2. Flush the toilet once a day. Conrad peed outside, over a cliff.
  3. Minimal clothes washing. We occasionally hung the dirty sheets out on the clothesline just to freshen them in between washings.
  4. We showered together. I learned that Conrad took much more time showering than I – lathering and preening! He’s the one who had been solicited by Bali Fitness to appear in their print ads, and even though that was years ago when the company was still Vic Tanny,  he still has a beautiful body and his white Karl Lagerfeld hair is full and fluffy, but c’mon, we had to restrict water usage!

We survived and at the end of the day, those two lovely months are the ones we talk about most when we reminisce about our travels. And we grew so close while out there – we even match our strides to each other when we walk and as we go about our days we’re always aware of where the other is – as if we are each one-half of a whole.

remote house sitting and immersion travel in Spain

Now, I think of our little adobe home whenever I turn on the faucet in our modern kitchen.

The water runs so free – and it would just keep coming if I wanted it to. But of course I use a great deal less than ever before, remembering how an algebraic equation kept us in water – however tiny the amount – for our glorious days on that remote mountain in Spain.

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6 Responses to “How an Algebraic Equation Saved Our Hides”

  1. Wow, this should be sent to kids in school as a reason to hit the textbooks! Isn’t it incredible (and scary) how much water we use and not even realize it?…
    Pola (@jettingaround) recently posted..Photo of the Week: A grocery store in FlorenceMy Profile

    June 26, 2012 at 1:43 pm Reply
    • Yes Pola, it is scary how much water we use. We’re all pretty spoiled, you know? Since that house sit, I look at many things differently.
      Haha — in terms of the algebra, Conrad’s niece is a high school math teacher and she told them this story. She said it made the students really pause to think!
      Thanks for stopping by. . .
      Josie recently posted..How an Algebraic Equation Saved Our Hides My Profile

      June 26, 2012 at 2:58 pm Reply
  2. Great list for house-sitting. We just got back from a week of house sitting in town.

    September 18, 2012 at 8:42 am Reply
    • Thanks — and welcome!

      September 18, 2012 at 8:50 am Reply
  3. I love that your husband peed over the cliff every day. What a crazy story, but thank goodness you both were resourceful and figured out how to make the best of it. The same old all the time is boring anyway!
    Diane recently posted..Lonely expat problem: Making friends is harder than it looksMy Profile

    January 30, 2013 at 6:16 am Reply
    • Hey Diane,
      You’ve made me feel better about my off-color content! I worry it will not be appropriate.
      Thanks for chiming in! Here’s to non-boring!

      January 30, 2013 at 7:21 am Reply

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