16 April 2009

Water harvesting - self reliance, preparedness and common sense

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



  1. Hi Rhonda Jean a timely post for us as we have just drained our tank to remove it from the stand as the pipes that hold it are rusting through. Hubby is interested in how you have the downpipes go underground and back up to the tank. Wouldn't it back up in the gutter? He likes the idea of putting the tank on ground level. Could you just mention that bit or show a pic. Thank you for all your words of wisdom that you share with us.
    Patricia in North Queensland

  2. This post is of real interest to me as I decided last week that I need to get to grips with my back garden. I know that I wish to plant fruit and vegetables so am currently reading up about what to plant, plus I wish to install a compost bin and water butt.

    I have been reading your blog for some time but until last week I just read and wished but did not action in anyway. That is, until this last weekend when I thought 'just do it!' So, I have started knitting a cardigan, knitted three squares for a throw for this winter, and made a chicken soup using up a chicken carcass for the very first time! So, a thousand thanks from a soon to be 45 year old who was in a real rut but who now feels renewed when I wake up.

    Many belated birthday wishes too!


  3. Hello Rhonda,

    Once again very sound advise. When we lived on the farm we had a 23,000 gallon cement tank that was still going strong when we sold after 20 years. That carried us through many drought years and we were even able to help out a neighbour who had run out of water in one very bad year. He was able to shower at our place and take some water home for his cooking etc. Water, food and shelter are the most important items we need to survive if things turn really tough. So again thanks for the timely reminder.

    Blessings Gail

  4. This is a great post and one I'll be saving for my next, and final, house building. Love the new blog design too.

  5. Rhonda,

    What a great idea! I know we have tried to collect rain water from our roof before but found it to be pretty dirty from the stuff our roof collected over the dry times. I would agree that it may not be suitable for drinking unless it went through some sort of filtration system.

    My daughter just finished building a green friendly house for her science project last year and this was added to her house to supply water for gardening. I had to show her yours, since we hadn't found anyone that actually had one and was using it.

    Thanks again,

    Love and Hugs ~ Kat

  6. Hi Patricia, I'll come back to your questions. Hanno has taken Kerry and Sunny up the mountain to look around.

    Elizabeth, I just loved your comment. I'm so pleased you decided to dive in. Remember, small steps and stick with it. Hugs

    Gail, I look forward to seeing where you two eventually buy your new home. Don't forget to factor rainfall and climate into the equation. If we returned to NSW, we'd probably look around the area inland between the Qld border and Evans Head. You'll notice a big drop in home prices out of Sydney. Good luck, I wish you a fruitful search.

    Hi Kristy and Kat. : - )

  7. Our neighbours raised some eyebrows when we installed three water butts in the back garden, but we've never had to use the tap to water the garden. My husband hooked one of the water butts to a pipe system to the greenhouse, and the pump is run via a solar battery. So the veg are watered on a timer via a drip hose, and we can go on holiday without worrying about the greenhouse plants.

    I would think in a very dry Australia that water tanks would be almost mandatory; then again, when I grew up in dry Colorado, there was water rationing instead of a campaign to get people to use water butts and tanks, lol.

    Thanks for your blog, Rhonda. Always great to read.

    AM of the bread

  8. I love collecting rainwater! I don't have to feel guilty about watering the garden, flushing the toilet or all the clothes washing I do. We have bladder style water bags under our house (rain reviva). Perfect for small yards.

    We have around 10,000L across two bags. We have it plumbed to our laundry, toilet and garden. I find it is a great way to becme more aware about how much water we use. I could not believe how much water we used over christmas when we have a house full of guests! So much water down the loo!

  9. Thank you so much Rhonda Jean & Hanno for the detailed explanation. Hubby is a bit concerned that debris would build up in the bottom of the pipework as we always have a lot of rubbish in our gutters. Perhaps we need some sort of gutter guard. We shall investigate further.
    Also hope you had a very special birthday yesterday
    Patricia in North Queensland

  10. Thank you for the thorough coverage of this important topic. We started serously investigating the installation of a rain barrel when our city recently offered rebates. But the cost (we'd have to use an approved vendor for the barrel) didn't make sense. Then, I read somewhere that rainwater collected from an asphalt roof (all the houses in my neighborhood have an asphalt roof) would not be suitable for watering vegetables. At that point I dropped the issue. Just curious if you or any of your readers have any experience with using water collected from an asphalt roof? Thank you.

  11. Those in the U.S. should be sure to check local/state laws before installing a system as water harvesting is not allowed in some areas.

  12. Thank you for the post, Rhonda. I have a question. Our roof is made of asphalt shingles. When I have collected water in the past, it has black, gritty bits in it (presumably from the shingles.) I know this can be strained out. But it seems like it would collect in the bottom of storage tanks and would make a very large tank very hard to keep clean!

    I also wonder if there are any chemicals in the shingles that I shouldn't be exposing us to, or pouring on our food as it grows.

    Thank you!


  13. Oh, thank you so much for going into detail on the rain water gathering. I have a question but it is a bit off the subject. In your post on making your own laundry detergent you said to not use the washing soda or the Borax, I forget which, if you are using your gray water to water plants. Why? What is in them to harm the plants? Is this warning for only flowers and our lawns as I take it we should not use gray water to water fruit trees or our garde anyway...am I right? Also we have asphalt roofing shingles...will the rain water from our roof harm our veggie crops? Jody

  14. Excellent topic and sage advice..always. :o)


  15. My husband installed a rain water cachement for me a few months back, and I'm very happy with it. My houseplants have really been happy with it, they have grown a lot better & faster now that they are getting rainwater. But as someone mentioned already, in the US you need to check for local ordinances depending on the area of the country you live in.
    Happy Birthday, sorry I'm late!

  16. Hi Rhonda

    A great outline on water tanks! Very easy to read. Just a comment about using the water - it is most water efficient to plumb inside to the toilet and laundry. That is because they use water daily unlike a garden which will use water seasonally.It will cost a bit more but most rebate requirements now insist on it. The good news for Australians is the federal government has just announced some fantastic rebates - $500 for rainwater tanks. Many state governments also offer up to $1500. So its really quite affordable!
    cheers Rebecca Blackburn

  17. I am curious about the poly tank. Is that safe for the veggie garden? I saw you mentioned food grade liners or such...could you elaborate on that a little?

  18. For those who have an asphalt roof and want to know about the suitability for water harvesting - I'm sorry, but I have no experience with that type of roof. I doubt I've even seen an asphalt roof. Please do some research before you start harvesting your rain water if you have that type of roof. Road asphalt does contain a lot of chemicals and if it's the same type of asphalt, it would not be a good idea.

    Jody, it was the borax. It is biodegradable, but it takes a long time to degrade and will harm your plants when the boron build up in the soil. It's not a long term problem, but your plants won't survive for long when there is a lot of boron in your soil. Here is some more reading: http://www.spectrumanalytic.com/support/library/ff/B_Basics.htm

    Autumn, we had our metal tank lined, the poly tank is food grade so it is unlined.

  19. Hi Rohnda and Hano,

    This is a great idea. I have never thought about the savings in saving water.

    We have a deep well that supply 40+ gallons per minuite. When the power goes out the pump changes over to the generator, and water moves on. We have never had a shortage here.

    But this is helpful in that the water tanks would be handy in the garden, to run a shorter hose from the tank instead of the faucet on the outside of the house. In our cold climate the tanks would need to be drained in the fall.

    Thanks for this info. I bet 55 gallon plastic drums would be a good resource.

    Thanks again for this wonderful idea!


  20. I just watched the rain fill my new 55 gal barrels. I have four of them and the fill so quickly that the rest overflows. I wish I had the resources to install a big system like you have because I certainly could fill it. I could have filled my barrels three times today. I live in Texas, USA.

    The water which is kinda "dirty" in that its rolled off the roof and through the gutters with leaves, etc, is beloved by the plants. Much more so than city treated water.

  21. This is very interesting to me, and I'd love to do this at some point, however I have a question. How do you keep bugs out of the water? I have a small water pond out back and the bugs are profuse! I have to scoop them out every day. Even if you had screen mesh, wouldn't there be little flies in it? Does the water get smelly from stagnation?

    Just curious before I daydream anymore about getting one :o)
    Hugs to you!

  22. Hi Heather J, there is fine mesh over all the inlets. Mosquitoes can get in but we've never had a problem with them being in there. The water never gets stagnant. I sometimes drink the water in our tanks and I use it to make my soap. It's always clear and sparkling.

    It's a good idea to keep your gutters free of rubbish when you have a water tank. Hanno gets up on the roof every few months and clears ours out.

  23. Thank you for your tips on water saving. this has been on my mind a lot.

    Also I don't suppose you would post on my blog the recipe for the canned pickles (?) on the right side of your blog would you? They are beautiful!


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