Water harvesting - self reliance, preparedness and common sense

16 April 2009

This is our 10,000 litre poly tank. It collects water from the shed that it sits next to and also from the house. The photo below shows how it's connected to the house.

I love rain. I love knowing it's watering the vegetables, being harvested from the roof and stored in our water tanks. Storing water is the same as storing an abundance of vegetables or fruit. You collect it when there is too much and store it to use when there is none. I have written about harvesting rain water before here, here and here, but I want to revisit the topic to encourage all the new gardeners out there towards some sort of water harvesting system. It can be as simple or sophisticated as you like, but if you're growing a garden, you should think about storing water. Water is precious and if there is no rain, your efforts at harvesting water will allow you to keep your plants going for a while longer before you have to rely on town water.

Hanno hooked up the house to the poly tank by running this downpipe underground and over to the collection tank.

Harvested water fits well within a preparedness strategy as well. If you have stockpile cupboards inside that will see you and your family through a crisis, then water barrels containing harvested water will fit right in with that way of thinking. Just like your stockpile, you can be using your rainwater throughout the year, but if there is a need for it, that water will be there to use more sparingly throughout the crisis.

We installed our first water tank as soon as we moved into this house about 11 years ago. That one was a steel tank that holds 5000 litres. A couple of years ago, when the rebates came in, we got ourselves a 10000 litre poly tank and those two tanks have not been empty at the same time since we installed the second one. We only use the water in our tanks for the garden, the animals and outside cleaning.

It will cost some money to buy the materials but over time you'll recoup that cost because you won't use as much tap water. It's also an environmentally sound practice. Instead of wasting that water that would go down the storm water drainage system, or into a creek or river, you'll capture that amount and use it when there is no rain.

Water tanks come in all shapes and sizes. There are poly tanks and steel tanks, all with food grade lining, that can fit into just about any space. They're usually round but some are oval, and some are like a wine cask bladder that will sit, out of sight, under decks. You'd be well advised to buy the largest tank you can afford, depending on the rainfall in your area.

I can't give general guidelines about water tanks or barrels because climate differences really do effect how and where you install your system. For instance, where we live, in summer there are torrential downpours which means we must have our overflow going to an area where it runs directly into our creek. We don't have to empty our barrels in winter to avoid the water freezing and cracking the barrels. Climate plays a big part in the size of the tanks but also in how you hook up your system. If you buy a larger tank, the store you buy it from will have instructions for that particular type of tank ans you should be guided by that. But overall, you must make sure your tank or barrel cannot be accessed by children or animals.

This diagram is from the Rapid Plas Sales catalogue - 2006. Click on the image to enlarge it.

To find water tanks in your area, simply google "water tank xxxx" xxxx=your area.
There is a lot of information on these websites.
Bluescope water tanks USA
Water tanks California
Water tanks North Carolina
UK Tank Shop
UK Water butts
Information about tank foundations
Rainwater harvesting
How to install a rain barrel
Rain barrel system - with photos
What size tank? Where do I position the tank?
Installation guide
How rain barrels work

Click on this guide to enlarge it. It is from the Rapid Plas Sales catalogue - 2006.

If you choose a large water tank it must sit on a stable well compacted base free of rocks, sharp objects or stones. Hanno put our last tank on a compacted base of crusher dust, with retaining walls, and it's withstood torrential rain unharmed for the past couple of years.

Traditionally in Australia, the old timers sited their tanks high on tank stands which assisted in the gravity feed of water. We have our large tanks on solid ground and use a pump on each tank to deliver water to the gardens. However, our newest tank, a small 500 litre barrel, sits on a stand, just off the front verandah, that is high enough for us to place watering cans or buckets under the tap.

You don't have to spend a lot of money to harvest rain water. If you can find suitable second hand containers they will do very nicely as your tanks/barrels and all you'll have to do then is connect it to the downpipe with some plumbing pipes - you might already have these on hand. Don't think that it's not worth doing unless you can have a brand new state of the art system. Water harvesting is a big part of any self-reliance strategy and as such, made from scratch with second hand materials will do just fine.

If you have any problems with your tank or barrels, or are unsure about installation or purchase, ask your question in the comments and I am sure Hanno will be happy to answer your queries.

Patricia: This is Hanno's advice. To get water into the large tank you have to make sure the inlet on the tank is lower than the gutter on your house. You can easily check this by taking a garden hose full of water to the tank's inlet and get someone to hold it at that level. Take the other end over to the building and mark the height where it overflows. When the water pipe from the roof to the tank is low enough, it will empty into the tank. Regardless of how deep you bury the pipe, it will be full all the time and the water will flow whenever it rains. Make sure all the underground pipes are glued properly so no water leaks into the ground. This is explained in the installation guide link above.

Australians paying more for water but using less