There are good ecological and economic reasons why you should be gathering and storing rainwater. We asked expert Peter Viner, Design Director of Design 4 Plastics Ltd and inventor of Rainwater Terrace to explain
Q. What are the ecological advantages of collecting rainwater?
A. Climate change is a fact, not a rumour, meaning that extremes of weather are happening. In drought conditions it’s good to have a supply of water to nourish our plants and gardens without resorting to the mains tap and depleting our reservoirs – think of the dreaded hosepipe bans.
Conversely, our Water Authorities are ever more conscious of the need to prevent flooding when there’s too much of the stuff, and would like us all to collect some of it to give the drainage system a chance to cope, particularly in built-up areas.
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The technical term is ‘attenuation’ and sometimes this involves making our Water Butts leak so there’s room for the next deluge. All the better if we can put that water to good use in our gardens, “growing our own” and producing nectar for our insect friends.
Q. Why is harvested rainwater better for your garden?
A. Tap water contains chemicals such as chlorine and fluoride intended to keep it safe for drinking, but these are not good for many plants. Some plants are more susceptible than others, such as Bonsai. Rainwater contains less minerals and is slightly more acid. It’s not just the plants but also the structure of the soil that reap the benefits.
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Q. How much money can you save by collecting rainwater?
A. Most houses now are on a water meter, so every litre saved does save money. 1000 litres of water costs about £4 so a standard 200 litre water butt holds 80 pence worth which is 4p per 10 litre watering can. The more you have to water, the more you save. But it’s not only the money that counts, is it?
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Q. What are the drawbacks of traditional rainwater harvesting systems?
A. The answers to this question are what inspired the invention of Rainwater Terrace.
There are some very large tanks you can install but these are usually buried underground, cost a fortune and require electric pumps to get the water out. What we are talking about are Water Butts that typically comprise a container fed with rainwater diverted from a down pipe off the roof and a tap at the bottom to get the water out.
Water butt taps are notoriously slow and prone to leaking over time, not helped by the water pressure generated at the bottom. They are often supplied separately for self-assembly which can be a challenge. Rainwater Terraces have taps on the end of drain tubes to fill watering cans in 20 seconds and show how much water you have left.
Water butts can get a bit smelly if the water is allowed to stagnate. Debris from the roof collects in the bottom requiring an annual clean-out to get rid of the slurry.
Ever wondered where the term “Butt Ugly” came from? There are some very attractive Water Butts but most are utilitarian plastic containers that are better hidden away, unlike Rainwater Terrace that can live happily “front of house”.
Q. How easy is it to set up a rainwater butt?
A. Fitting a diverter to your down-pipe is pretty simple, usually involving a couple of saw cuts through the pipe. The majority of plastic downpipes are 68mm round or 65mm square and the standard diverter has an overflow feature that allows some water to go straight through in a deluge or when fitted below the top level of a traditional Water Butt to prevent it overflowing.
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The patented Rainwater Terrace is different because the diverter must be fitted higher than the top so that water can overflow internally to fill the lower containers, water the plants and keep the water fresh by flushing any excess back to the drain or into the garden. Its modular construction is easy to put together with no tools.
You can also collect rainwater from a shed or greenhouse in which case there are adapters to take all the water directly into the water butt.
It is important to have a flat, level base to stand it on. 200 litres of water weighs 200 kilos so this weight should not be underestimated.
Q. How do you get the water out of a Rainwater Terrace?
A. There are drain tubes on each level that show how much water there is inside, and each has a tap on the end for filling watering cans in about 20 seconds.
Q. How can I expand a rainwater harvesting system?
A. Traditional water butts can be joined together sideways by having an overflow pipe from the first one fill a second one. This must be slightly below the level of the diverter otherwise it will never fill and each water butt needs its own tap. Rainwater Terrace is essentially a collection of 67 litre water butts stacked on top of each other and can be connected sideways in such a way that only one drain-tube tap is required on each level.
Q. Are rainwater harvesting systems safe for pets?
A. Yes, so long as there is a lid on it. They shouldn’t come to any harm if they drink the water either.
Q. What other uses are there for harvested rainwater?
Rainwater is softer so good for cleaning the car without smearing. The water must be clean of course, which is the case when using a Rainwater Terrace where the natural filtration created by the various overflows leaves the water in the bottom container really clean. I would dare to wash my hair in that! (I do have some left).
Rainwater is also good for watering indoor plants, but without chemical purification it wouldn’t be suitable to drink – it will always contain come chemicals and bacteria from your roof or gutter.
Q. How can I make a rainwater harvesting system look good in my garden?
A. There are some good-looking water butts about, some in the form of Roman pillars or Greek urns, and some have planters on the top; but the Rainwater Terrace is the only one with side planters to really make a feature of your water butt. Planting herbs and fruit as well as flowers make it productive too.
Find out more about Rainwater Terrace’s beautiful water butts here.
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