But what are we going to drink? Harvesting Rainwater in New Zealand
Our water source was one of the first things we thought about when we bought our property. We knew there was no access to town supply, so securing our water source by getting set up to collect rainwater was a top priority. From Mark’s experience of growing up on a farm, he knew that water can be the difference between plants that grow and plants that die. Of course, we also needed water for drinking, cooking, and washing.
As part of building our heritage-style barn, we had a 30,000 litre polyethylene water tank installed. Mark was particular about positioning the tank as close to the barn as practical. This surprised the builders; they couldn’t figure out why we’d worry about saving a few metres of space when we had plenty to spare. But by keeping the tank snug up against the barn wall, we’ve been able to use the space between the building and our boundary for our driveway. A much better use of what otherwise would have been dead land due to the local council’s requirement that any buildings be at least eight metres away from a boundary.
Inside the tank is a pipe (known as a Riser Tube) that runs from the overflow outlet at the top to the bottom of the tank. This means that when the tank is full to overflowing, a vacuum-like pressure is created to ensure that the water that flows out is drawn from the bottom. Because sediment and particulate are heavy, they tend to be at the bottom, so this solution means that if the tank overflows, we’re losing the ‘least-clean’ water first.
The pump house was the first DIY project we completed. Mark hadn’t built anything for years but knew exactly how to design and build the perfect little shed to house the Italian-made pump he’d ordered online. With the help of YouTube and Bunnings, we could quickly use the pump to access our harvested water via a simple outside tap mounted on our retainer wall. That tap provided the water source that made it possible for us to choose to move into our just-finished barn when the pandemic was declared a few weeks later, and the country was locked down.
That first year, we only had that 30,000 litre Baileys tank. We used the water collected off the roof for all our household water use and to supplement our grey water system to water the trees we planted on our property. We added a second 30,000 litre tank in our second year of living on our property to maximise our rainwater harvest. We connected the two tanks via a pipe at the bottom of the tanks, which means that the water flows between the two, and each holds an equal amount of our stored water. Mark spent a lot of time looking for a tank gauge that would allow us to monitor the water level in the tanks remotely. He also wanted to be able to track our consumption, as well as how much water we collect when it rains. We went with the battery-powered Bluetooth-enabled Tank Gauge Plus by Blue Mountain Co, which was easy to install on the top of the tank. It means we can monitor our tank level from almost anywhere.
The third tank we added was a 10,000 litre Baileys tank to harvest the rainwater from The Bath House's roof, a wonderful indulgence to which I’ll dedicate a future blog. All three tanks are interconnected, allowing us to pump water from the highest to the lowest or vice versa. The 70,000 litres of water storage capacity gives us a lot of confidence that we’re self-sufficient from a water perspective.
