Rainwater harvesting - your experiences

[contadina]

I was just looking at the price of 100,000 litre tanks and worked out at our current usage (let's say 200m3 including garden p.a.) it would take us about 49 years to break even.

I can't see us ever getting enough rainfall to fill the whole thing twice a year though!

You'd be surprised MMM, ours only fills in the winter and we've never had to buy water despite having very long droughts every summer.

Rainfall profiles are really important: we don't get any rain from May to Sept, temperatures are consistently high, so we so need to water the plants more often and we need daily showers. Factoring this all in means we need a much bigger cistern than someone in Northern Europe.

The capture area is important too, if it was just our roof we'd never fill the cistern, but as we capture rain off a much bigger area, which is sized for our cistern, it's always full as summer arrives.

One other addition we are going to have this summer is a small cool-pool to sit in and cool down . It will built in cocciopesto (lime mortar with crushed pottery/hydraulic lime and filled crushed bricks), and be filled each morning via a submersible 12v and a PV panel. It'll have a read/float switch, so stop once it's full. In the evening we'll turn a tap to empty the cool-pool and the water will then be used to irrigate plants. It's taken us a while to work out a system, which doesn't require electricity to fill and enable us to reuse the water. I can't wait .

[Millymollymandy]

I hadn't realised that IBCs were so short lived either, that's good to know as I was considering investing in a couple.
Zoe

Zoe I have been looking around on several websites which sell different kinds of taps and all sorts of plumbing paraphenalia for IBCs and hope we can manage to replace ours - the problem being some of the connections are in a recessed bit surrounded by the metal bars of the cage and my OH just cannot get in there to disconnect them. It seems to be the taps and connections which go (start to drip) rather than the IBC itself.

Another thing I forgot to mention is that the water in a white IBC can go quite green after a while if no rain falls, that's not a problem for watering the garden but when it gets bad I don't like to use it for the feathery ones. I know you can get black ones but then I wonder how you can tell how full they are?

Hedgie - I do use two watering cans! I can't time it easily for one to fill whilst I'm watering as it's quite a walk to the other end of the veg patch.... easier to fill two and make fewer journeys...

Contadina - I realise if I lived somewhere like you do I'd need to get far more of our roof space connected to water storage than we currently have - but it's the the cost of the 100,000 litre tanks starting at something like €26,000 that is quite ridiculous, so it would be much cheaper to just use mains water. The same is true for the cost of IBCs vs how much they save us - the truth is they don't really - they are just handy having the water where it is needed.

[Thomzo]

Thanks, all. This is very interesting.

MMM, one thing that I discovered during my research is that both CAT and the Environment Agency say that it's pointless running a rainwater harvesting system with a pump from both a financial or environmental perspective if there is mains water available (in the UK). The cost and embedded CO2 in a pumped system are both higher than using water from the mains. I don't know about the equivalent costs in France.

Maybe I'll try freecycling some plastic dustbins. We got wheelie bins a couple of years ago so there must be lots of unused dustbins around hereabouts. They seem to make the best waterbutts, if a bit small, as the plastic seems stronger and they are black so keep the light out.

Zoe

[contadina]

It only costs around €6-8,000 here for a cement cistern of that size, less if you need to cut through rock and use blocks rather than cement. Okay, so still not a cheap outlay, but as most of my neighbours have to pay for 8,000-litres of water to be delivered every week or so during the summer at €30 euros each time, it must have paid for itself fairly quickly.

[Thomzo]

It only costs around €6-8,000 here for a cement cistern of that size, less if you need to cut through rock and use blocks rather than cement. Okay, so still not a cheap outlay, but as most of my neighbours have to pay for 8,000-litres of water to be delivered every week or so during the summer at €30 euros each time, it must have paid for itself fairly quickly.

Gosh, certainly puts my water bills into perspective. I shall certainly stop moaning about having a water meter now. Thanks, this is a good comparison for my assignment.

Zoe

[Millymollymandy]

I do think that everyone on mains should have water meters as it does make you appreciate how much you use, and using it on your garden (whether from stored water or mains) makes you appreciate it even more. Then there is the double edged sword of growing your own veg, particularly lettuce, which needs at least 3 washing up bowls of water to wash, vs. clean clinical almost bug free supermarket lettuce which only needs one bowl.....

Now if only my lake would hold water during the summer months I would never have a problem but the only time it stayed full was during our only wet summer in 7 years - consequently of course I rarely needed to water the garden!

[Henwoman]

In my garden I have a 4m gutter on the woodshed draining into a water butt which has a hose going to the fish pond to keep it topped up. In the driveway I have a waterbutt taking water from the house roof which I use to water the terrace and driveway plants.

On my field where I have no water supply, I have a barn with a 5m gutter. We have made the gutter peak in the centre so that it fills an IBC at each end. At the back of the barn, the IBC is connected to two others so that they all fill eventually. I also have two water butts at the back of the polytunnel which I fill via hose from the first IBC. I have four ordinary house baths which I fill from the IBCs when they are full, one of these baths is in the middle of my polytunnel so I can just dip my watering cans instead of waiting for slow hose filling, and the other three are placed strategically around, one in the goat/hen fields, one by the front veggie beds and one waiting to have the plughole sealed with wood and silicone so it can be filled. There are two 500 litre galvanised round containers which are also filled by hose from full IBCS which are in the animal fields. I also have a duck pond in the duck field which just fills with normal rainfall - no springs on my land unfortunately.

Also I have a large - perhaps 600 litre stainless steel dairy container, like a large bath which the IBCs hose fill and another smaller ss dairy container too.

Last week at the tip I picked up a 500ml container like a giant green flowerpot. It has a small crack in it which will be mended successfully with WetGrab and used for water next to the runner bean bed. I am also waiting to collect two more IBCs which were advertised on a local expat website.

I am religious about filling anything other than IBCs from the IBCs as soon as they are getting low, so that I always have the maximum possible water stored, as transporting water to the field in large enough quantities is a nightmare I want to avoid having done it two years ago when we had a very dry September, October, November. Even my watering cans - about eleven of them - are kept full. I am obsessed with water collection!

[Henwoman]

If anyone in Brittany, or perhaps France generally, is reading this. I bought five 11 litre dull green watering cans from SuperU this week for €1.95 each - brilliant value. The same ones I always buy, but cheaper than ever.

[happyhippy]

When I lived in Australia,I had two huge galvanised water tanks.One was connected to the house roof,the other to the double garage.The house one was plumbed into the house and outhouse.So I had rainwater(and mains!!!)for cooking ect,and the outhouse was used to wash clothes,either by hand or machine.The garage one was used to water my veggie plots.
At the moment I am living in the UK,and I have two water butts,which I'm about to connect to the guttering off the house for watering in general.It was crucial really for me to have water tanks in Australia,too much drought.I mainly do it here because I like to feel abit more liberated and not have to totally depend on water companies for my water.

[tim_n]

I have 3 IBCs. I have found the taps are fine at the moment but rather than rely on them, I need to replace them with proper metal jobbies so I use the internal taps as little as possible.

My replacement caps which convert from IBC to hoze leak a lot. I'm going to try PFE tape.

The IBCs do go green. It's best to box them in. It's on my to do.

Regardless of calculations saying that rainwater that is pumped is not financially viable, if like in the SE of England they're considering a hoze pipe ban due to the drought and talk of standpipes etc they could be a lifeline for a garden. Plus they're better for plants too!

[Thomzo]

Bump - sorry guys just bumping all the threads relating to my project so that I can access them easily. I'm in the middle of writing the last assignment now. I bet you'll all be pleased when this is over, I know I will.

Cheers

Zoe

[wulf]

I do think that everyone on mains should have water meters as it does make you appreciate how much you use, and using it on your garden (whether from stored water or mains) makes you appreciate it even more. Then there is the double edged sword of growing your own veg, particularly lettuce, which needs at least 3 washing up bowls of water to wash, vs. clean clinical almost bug free supermarket lettuce which only needs one bowl.....

Getting a water meter fitted has been a long-running saga; the point it was originally fitted turned out to be on a shared supply, resulting in a much higher bill than expected. However, we have ended up with a new meter actually inside the house; this vindicates our water saving strategies as my wife and I use about the amount expected for a single person despite doing a lot in the garden. In just one hit, the bill reduction more than pays for all the hassle of getting the meter correctly fitted!

One of the strategies we employ to save water is to throw away as little as possible. Water from washing vegetables gets used to water edible plants in the garden or polytunnel; during hot spells all but the greasiest / soapiest of washing up water also gets used for for the ornamental plants in the garden.

Wulf

[Thomzo]

Sounds good, Wulf. Another advantage of not throwing washing up water down the drain is that you're less likely to block up the drains.

One of my biggest problems is that my kitchen sink is a long way from the boiler so it takes a long time for the water to run hot. I keep a watering can on the kitchen windowsill and fill it while I'm waiting for the hot water to come through.

Zoe

[Durgan]

http://www.durgan.org/URL/?SSCLP 22 March 2012 Rainwater barrels connected to down spout.

The four drums connected to the house down spout. There is a total of 200 US gallons (800 litres) of water. The connections are removed in the Fall and the barrels emptied to prevent freezing. The fittings are all standard. Barrels cost 15 dollars each. Water is pail dipped from the open barrel and transported by wheelbarrow to the garden area. Overflow is from the top bungs and simply goes onto the grass.Many barrels could be placed in tandem, but I find four barrels meet most of my requirements. The system is basically closed, since if not monitored they can be a breeding reservoir for mosquitoes. The supports are steel fence posts with a metal sling to hold the barrels.

http://www.durgan.org/URL/?SCEIG 17 May 2012 Transporting Water
My yard is large and it is necessary to transport water from my four 45 gallon drums rainwater to the plant area. The rainwater is run into a 45 gallon drum and had dipped by pail into the wheelbarrow. I have four collection barrels two on each side of the house.A milk crate is placed in the wheelbarrow, and this inhibits wave action and spillage, when wheeling to the plant area. The wheelbarrow hold about 90 litres of water. This method is much easier than carrying two 20 litre buckets each trip. The pail used for dispensing is perfect for dumping the water on the roots of bush plants, and the water can be placed in a watering can for more delicate situations. Using this method I find watering a pleasure, quick and not onerous.