Rainwater Harvesting Part 2: Our First 2,000 Litres of Rainwater—Captured!

Rainwater harvesting has always been part of our permaculture homestead plan. But we set it aside while we concentrated on establishing the house and gardens and tending to our farm animals. The project became a priority with the devastating drought and wildfire seasons of 2017 and 2018. That experience, coupled with long-term climate change trends, motivated us to act now. Here’s a brief account of our story… so far. 

This photo was taken in early June, before the tank had filled. Also, this tank has a capacity of 1,000 litres. Its mate is collecting rainwater from our rabbitry roof in another part of the farm.

Step 1: Getting educated takes the mystery out!

At first, the term rainwater harvesting sounds remote, abstract and far too complicated. But there are many resources online that explain the considerations in building a home-based rainwater harvesting system for those of us who are not builders or engineers. 

We chose a six-week course offered by Alberta-based Verge Permaculture, founded by Rob and Michelle Avis, professional engineers and permaculture consultants. Their rainwater harvesting course offers a mix of printed, audio, and video resources, with weekly live Zoom meetings featuring the expertise of Dr. Peter Coombes, a scientist-engineer and  rainwater harvesting consultant based in Australia. 

We’re planning to use what we learned from this course and the accompanying handbook when we build our main household rainwater system. For now, our pilot project will give us hands-on practice as we capture some of our more abundant Spring rain in preparation for the upcoming dry months. 

Step 2: How we set up our low cost, low tech pilot project 

Why a Pilot?  When we began building our homestead, the first straw bale structure was our cabin, a 350 square foot multi-purpose building. The lessons we learned helped us avoid mistakes and make functional and aesthetic improvements when we built the main 1500 square foot house. 

Buildings: We decided that our chicken coop and rabbitry would make ideal starter roofs to test rainwater capture. The financial risk was low, relative to embarking on the full household system, and the water we harvested would support animal care and nearby fruit and nut trees. 

Materials: We bought two used food-grade 1000-litre (275 gallon) IBC tanks, or “totes”,  for $225 each. (They sell for about $650 brand new!)  The rest of our materials—roof conveyances, attachments, eavestroughs, and leaf diverters to filter debris—brought our total cash outlay for both systems to a modest $800.  

Timing:  The chicken coop system was installed in the last week of May, just in time for an extended 35-mm rainfall the weekend of May 30-31. The rabbitry system was completed a week later.  We were in business! 

Step 3: Modifications to the setup 

With COVID-19 supply chain issues, some parts are not currently available, but we didn’t want to wait. So Susan used a temporary, inventive workaround to complete the assembly. It worked! On the morning of May 31, we were thrilled to see the chicken coop rainwater tank water level up to the 400-litre mark. 

As the rain continued to fall on May 31, Susan observed a gap in the conveyance from the roof to the eavestrough, resulting in less rain capture. She closed it off with flashing, ensuring all the roof rain would flow into the tank. Over the next week, the tank water level rose to nearly 700 litres at the coop. Not bad for a trial run! 

Between early June and Canada Day, both tanks filled to capacity.  We have drawn about 400 litres, and this volume has been fully replenished, ready for the dry weeks of midsummer. 

We expect to empty the tanks before harvest, and retire them for the winter months. Early next Spring, we’ll reconnect the tanks at the coop and rabbitry. We are also considering adding another tank to the rabbitry to take advantage of its relatively larger roof area. 

Step 4: Looking ahead to the house rainwater harvesting systems    

These are the earliest days for our rainwater harvesting plans. Over the Summer, we’ll closely monitor how well the outbuilding tanks perform and make adjustments to optimize performance. 

Together with the foundational knowledge from our course through Verge Permaculture, this pilot project will help us plan and build the cabin and house rainwater harvesting setup. 

The permanent rainwater harvesting system we design will capture as much as 20,000 litres. It will be easier to manage, more durable and flexible. We are also investigating the feasibility and affordability of frost-proofing to allow for winter snow-melt capture as well. In the meantime, it is satisfying to be harvesting as much precious water as we can for homestead use in the dry weeks ahead.

Learn more in Part 1: Why We’re Investing in Rainwater Harvesting 

Anne Mowat is an EcoSociety member and a volunteer with the 100% Renewable Kootenays campaign. She lives off-grid in a solar-powered straw bale house in Glade with her spouse, Susan Risk, their English Shepherd, Charlotte, and cat, Solly. Over the past decade, they have been gradually developing a permaculture homestead, and now grow much of their own food, including produce, eggs, and meat. A veteran PR professional, with degrees in business (Queen’s) and journalism (Ryerson), Anne still consults part-time from her home office.