GeneralWaterWater Harvesting

Water-Farming Part 2: Practical Ways to Harvest Your Sky-Fruits

In Part 1 of this article (1), I went over the importance of incorporating water and water flow into any design you make, as well as sharing some ideas about how, if we want to encourage using water in a way which is beneficial for ourselves and our environment, we need to also reconsider how we relate to this element  (for more ideas about this see 2).

The easiest and most efficient way to get more water into your design is to harvest the free and abundant fruit of the sky which drops as rain, pretty much everywhere in the world, though not always at the same time as you want it.

In part 1 we looked at Brad Lancaster’s formula (1, 3) for calculating how much rain you can catch in a particular area, while in this article I will go into more detail of what to do with that water once you have harvested it.

The water-harvesting principles

Following the permaculture design principles (see for example 4, 5) in your water design can help you to create a holistic, effective system. But did you know that as well as the permaculture design principles, Brad Lancaster has also helped to popularise eight water-harvesting principles?
These, in many ways, harmonise with the permaculture principles and indeed some are very similar. I have found them very useful as an independent toolkit to help with my water system design as well, however, so I shall also quote them here:

“1. Start with long and thoughtful observation” (3) – very similar to the “Observe and Interact” principle. Before you start changing your environment, first you have to figure out what is actually going on there. Lancaster recommends you follow this principle by going outside every time it rains and watching for patterns of flow.

Water Farming 01

“2. Start at the high point and work your way down”(3)- this is for maximum efficiency as you can, as much as possible, let gravity do the work, and the more water you catch higher up on your site, the more you can direct to other points lower down.

“3. Start small and simple”(3)- Lancaster began his rainwater-harvesting career by simply digging one small basin around a dying sour orange tree and directing runoff into it in his Tucson, USA garden.
“The results amazed us. After a single rain, the tree burst out with new leaves, a dreamy show of fragrant blossoms, and an abundant crop of fruit…”(3)

If you begin with small things you can learn from the results and thus progress.

“4. Slow, Spread, and Infiltrate the Water”(3)- this is the “three Ss”, slow, spread and sink, enabling you to re-fertilise and rehydrate the landscape and avoid erosion, flooding or drought.

“5. Always plan an overflow route, and manage that overflow as a resource”(3)- however predictable you think the weather is on your site, it can always surprise you, especially in today’s uncertain world. Also, if you plan for overflows to happen you can direct them to other points on your site that need water.

“6. Create a living sponge”(3)- the more vegetation you plant, the more the roots can help to hold the soil together and mulch from the leaves can help to build up new soil. This in turn is better able to retain water, and so support even more vegetation. And so the cycle continues…

“7. Do more than just harvest water”(3)- this is similar to the permaculture principles of “use multiple elements for every function” and “each function can be fulfilled by multiple elements”. With the extra water you can grow food, create shade, or many other functions. The only limit is your imagination!

“8. Continually reassess your system”(3)- so returning to Principle number 1 again. Keep on observing after every change you make, and note what is working.

Stocked with these principles you can start harvesting rainwater in any setting.


As well as calculating how much rainfall you can get from each particular surface within your site, Lancaster also recommends calculating your “water budget”, or roughly how much water you “spend” annually (3). Even if only a rough figure, this can help you to work out what percentage of your water needs you could be meeting with your water harvesting systems, and as such it can be an inspiring activity. If you live alone or with only a few people such a calculation may also be relatively simple. You can look up how much water most appliances use on average, and take into account things like how often you shower and how many cups of tea you drink in a day. If, however, the place you live or the site you are designing is a large community with complex water systems, such a “water budget” calculation may be time-consuming to arrive at and possibly irrelevant if you are not in a position to change much of the existing systems in place.

More helpful could be to try to roughly calculate how much water you need in the particular area you are designing, for example by counting the trees and looking up whether they are suited to arid or humid conditions, then looking up how many litres of water they need per year.

To tank or not to tank?

One way of storing your water in order to use it later on is in a tank or cistern. Whatever kind of climate you live in, investing in one of these is probably a good idea, since there may well be times when you want to use more water than what is falling from the sky. That said, we also need to remember two basic things about water harvesting: that water is an embodiment of flow and encouraging this flow is one of the most energy efficient ways of harvesting it, and that the best place to store water in order to increase fertility and encourage regeneration is within the soil (see for example 1).

So, if you’ve made your rainwater-catchment calculations and discovered that from your roof alone you can harvest hundreds of thousands of water in a single year, there’s no need to start panicking about all of the cisterns you will have to buy to store it all. On his 0.05-hectare site Brad Lancaster harvests annually around 100,000 gallons (378,500 litres) of water but the only closed cistern he uses is a 1,200-gallon (4,540-litre) tank. The rest is infiltrated into the soil around his site (3).

Such kinds of tank can be found online for less than $1000 USD and measuring less than 3m in height (see for example 6). However, if you are on a smaller budget than this, you can build one yourself. But how do you know what’s right for you? When choosing, firstly, it is highly recommended, by Lancaster and others (6) (7), that even if you are not planning to drink the water which you collect, you ensure that the tank is suitable for potable water. There are a few reasons for this. As Lancaster says,

“The higher the quality of the stored and harvested rainwater, the more options you have for its potential use”. (6)

Also, even if you are not drinking the water your plants probably will, and if you are incorporating the flow into your landscape it may well end up being ingested by other animals, so if the tank contains chemicals which could be harmful to humans they may also harm others in the ecosystem.

If you want to build your own water storage tank the most common designs which come up involve using cement. In a way this makes sense as cement is watertight and durable and so energy efficient in that the tank will probably require less maintenance than if you were to use other materials. However, the cement industry is one of the most destructive ones on the planet in terms of carbon emissions (8) so if you are able to do routine maintenance on your tank every few years or so it may be worth considering a different design. For example, Ron Finley published a design in Mother Earth News for a do-it-yourself water storage tank made mainly from welded wire and “organic roofing asphalt” (9). The design does not include a cover so you would have to adapt it to add one, since you want to be protecting the water from contamination from debris, and from evaporating.

Another possibility is to make an earthbag water tank. This is a tank whose main frame consists of earth or sand-filled bags, which frame is then coated with a layer of ferrocement – a mixture of lime or cement with sand and water laid over wire mesh. Because of the relative ease of the task of stacking bags on top of each other this method can be done by much less skilled or experienced water-tank builders than may be needed for other designs (see for example 10, 11). However, if you use lime in the ferrocement you have to consider the toxicity risks (12), while if you replace the lime with cement you have to consider the risks to the environment in general.

Another way

There may well be an alternative in your area to either of these two materials. For example, in the Alpujarra region of Andalucia, Southern Spain, the waterproofing building material of choice for centuries has been a type of magnesium clay known as “launa” or “laguena” (13). This material is readily available in many parts of the mountains and is non-toxic and naturally impermeable. It is worth considering if your local ecosystem can sustain harvesting of such materials, and if it can, it may be very effective to check out if there is a similar material to “launa” there. This information may well not be available online, and anyway it is probably recommendable to find observable working examples.

Whatever you decide to build your cistern from, if you are unsure about the potability of the water you catch in it you could always line it with a liner which has been designated as safe for drinking water (see for example 7). However, even if you do not have the resources to install a cistern right now you can be getting on with designs which can help you harvest the bulk of your water-fruit; i.e. the landscaping and earthworks.

Digging for harmony

Following principle number 2, “start at the highest point and work your way down,” (2) this point on your site is where you want to first place your shovel into the ground. What you dig depends on what the land is like already and what you want. At the high point of his land, Zephaniah Phiri created a large unlined, hand-dug reservoir known as the water “immigration centre” (14). From here he directs the water to different places and water catchment systems all over his site. As Lancaster reports,
“‘Rain, welcome to my country!’ he shouts during storms.
“Now I will tell you where you will live: in the soil!'”

Quite a useful article about different types of water catchment earthworks can be found on this site from Jonathan Engels (15).

If you have quite steep slopes you may wish to create swales (see for example 16) every few metres or so, and if they are really steep it may be worth building dry-stone terraces to help to hold the soil together. Even a relatively flat terrain will have some slope and if there are trees there already you can significantly increase the amount of water going to the trees just by digging simple basins around them. By following principle number 5, “always plan an overflow route, and manage that overflow as a resource” (3), you could create a “net-and-pan system” (see for example 14, 17) where the overflow from each tree-basin is directed to the next tree down the slope, and so on.

Water Farming 02

Where to start?

Now you have a little more information about catching and storing this wondrous aquatic energy. But what should be your next step? This, of course, depends on your personal situation and design plans. For me, although I am currently resident in a tropical climate where pretty much all of the annual rainfall occurs within a 6-month period, thus showing the need to store water from the rainy season in order to use during the dry season, as I wish to “start small and simple” I am beginning by concentrating on the landscaping and earthworks. For other situations, it may be easier or more desirable to first build a water-tank, or to redirect the flow of an existing waterway by changing the shape or material of a path, driveway or paved area.

However you begin, remember that one of the most important aspects of how we can use water in an efficient and beneficial way is to recognise the possibilities for abundance inherent within every system. A great way to start encouraging this culture of abundance is to celebrate everything. From throwing a water-party, incorporating sculptures into your design, getting involved in local water-conservation or regeneration activities in your area, or simple visiting a local body of water which helps you to feel calm or special – water is what brings us life so why not show your appreciation for it, in whatever way suits you?


1. Haworth, C, 2017. ‘Water Farming Part 1: Why and How Can We Start Farming Water?’ Permaculture News, 20/3/17.

2. Ashwanden, C, 2017. ‘Elemental Depths and Ideas for How to Dive into Them’. Abundance Garden, 20/3/17.

3.  Lancaster, B, 2013. Rainwater Harvesting for Drylands and Beyond: Guiding Principles to Welcome Rain into Your Life and Landscape. Volume 1, 2nd Edition. Rainsource Press: Tucson, USA (distributed by Chelsea Green: New York, USA).

4. Permaculture Association UK, 2017. ‘Principles’.

5. Holmgren, D, 2017. ‘Permaculture Design Principles’.

6. Harvesting Rainwater, 2017. ‘Water Tanks/Cisterns’.

7. Ameri-Brad Products, 2017. ‘About Vinyl Tank Liners’.

8.World Business Council for Sustainable Development, 2002.  ‘The Cement Sustainability Initiative: Our agenda for action’.World Business Council for Sustainable Development: Geneva. page 20, published 1 June 2002. Available as a PDF here:

9. Finley, R, 1981. ‘Build a Water Storage Tank’. Mother Earth News, 9-10/1981. Available online here:

10. Fouts, L, 2014. ‘Cistern part II’. LilyAnnFouts, 20/11/14.

11. Geiger, O, 2017. ‘Earthbag Water Tanks’.

12., 2017. ‘Calcium Oxide’.

13. Spiers, P, 2009. ‘Eco-casa: Roll out the Tyres’, La Chispa, 15/12/09.

14. Lancaster, B, 2010. Rainwater Harvesting for Drylands and Beyond: Guiding Principles to Welcome Rain into Your Life and Landscape. Volume 2. Rainsource Press: Tucson, USA (distributed by Chelsea Green: New York, USA).

15. Engels, J, 2015. ‘5 Fun and Fruitful Techniques for Small-Scale Earthworks’. Permaculture News, 4/12/15.

16. Haworth, C, 2015. ‘Understanding Water part 2: Working with Flow’. Permaculture News, 26/6/15.

17. Bogata Suma, 2017. ‘Permaculture: Net and Pan System in the Orchard’.

Charlotte Ashwanden

Charlotte Ashwanden (nee Haworth). Born in London, I am very interested in peace and community and have a degree in Peace Studies. I got my Permaculture Design Certificate in 2011, from Treeyo at Permaship in Bulgaria, and my Permaculture Teaching Certificate in 2018 at Aranya in India. For me, permaculture is about so much more than garden design; I am mainly interested in applying ‘human permaculture’ as a complement to peace practices. In particular, I like to look at how human permaculture can be applied through psychology, communication and education techniques. In 2015 I got married in a pagan ceremony in a field to David Ashwanden and changed my surname to Ashwanden. With my husband, I’ve travelled a lot in Europe and Asia and encountered many permaculture and community projects. I have lived in various situations, from squatted land to intentional communities, as well as more ‘normal’ places, in the UK, Spain, Italy, Thailand and Vietnam. A professional dancer, I do fire and hula dance and sometimes run dance meditation workshops. Currently, I live in the Andalucian mountains.


  1. Check out culvert cistern on youtube. Homesteadonomics has put in 2 that he recaps on his channel.

  2. I designed and implemented a rain water harvest system a little over a year ago. I have two 5000 gallon tanks which are connected with one pipe so they fil simultaneously. I live in Ramona, CA. So far I am filling up both tanks and going into overflow from one season of rain which for us is winter. I have to say there has never been anything as exciting as capturing rain except when your tanks are full. I am planning to continue to buy tanks and place in other areas on my property. I have a question though…I am curious is there something I have to put into the tank to keep it fresh or good for my trees and gardens? So far the rain water I use for irrigating throughout the summer seems to be more nutritious to my plants more than well water. They seem very happy. Just wondering if there might be a tablet or some kind of ionizer to make sure water is good. Or should I test the water? Please advise.

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