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Rainwater harvesting: isn't it just a large water butt?

Posted by Barry Nutley on 8 January 2009 at 11:40 am

For many people, the idea of collecting rainwater, doesn't seem as sexy as, say, solar, and I know from personal experience, it's not a conversation for a first date. But it is just as important as solar and other renewable energy technologies.

For my first blog, rather than write an essay on rainwater harvesting, I will start by answering some common questions. Please do leave comments and questions.

So to answer the question "isn't it just a large water butt?". Well,fundamentally, the answer is yes, but typically much larger, and with more uses.

What does it do?
Simply collects rainwater, which can then be used for non-potable uses, such as toilet flushing, washing machine, and of course garden irrigation. A typical, correctly installed system will provide water to these areas, on demand, automatically, assuming there is water in the tank. If there isn't water in the tank, the system reverts to mains water.

It's always raining in England, why should I bother?
The population is growing, and according to The Environment Agency, many parts of England are considered to have "serious levels of water stress". This includes London, the South East, and East of England. So whilst it is always raining in England, we still have a duty to save it where possible.

What is it going to save me?
As with all renewable energy technologies, this depends largely on the individual application. But if you consider that the average person uses 150 litres of water a day, and around half of this is for non-potable uses, then potentially it could halve your supplied water bill.

But that's not much
If you're on a water meter, then the financial savings will be higher. Your waste water bill is based on your supplied water. Therefore, if you use less water, then (as far as your water company is concerned), your waste water bill will be less in proportion. Also, don't forget the positive impact on the environment.

Is it right for me?
While almost any property will gain something, there may be more cost effective options. Retro-fitting can be costly, but if you are building an extension or conservatory, or landscaping your garden, then it's certainly something to consider.

So that's the first blog post. There are, of course, many other facts and figures which I will leave for another time, or if you just can't wait, please send me a message.

Photo by aussiegall

About the author: Barry Nutley is co-founder and director of Viridis Energie Consultants

If you have a question about anything in the above blog, please ask it in the comments section below.

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Comments

5 comments - read them below or add one

tomgrocott

tomgrocottComment left on: 29 May 2009 at 4:39 pm

Barry Nutley

Barry Nutley from Viridis Energie ConsultantsComment left on: 13 January 2009 at 11:14 pm

Hi Kris. Thanks for the feedback. I'm pleased you found it interesting. So, to try and answer your question. I think the easiest way is to break down a "typical" systems basic components: A storage "vessel" for the rainwater. A filter system. A pump. A control system. Plumbing. In theory, if you have all of these, then you can harvest rainwater in some way. The size of your vessel, of course is very important, which seems to be your problem? In order to size as vessel, we would, usually, look at the collection area (usually roof space), average rainfall for the area, and also, to a lesser degree, your water usage. Ideally, for full domestic applications, we would recommend an underground tank, as the temperature underground remains relatively constant which reduces any "nasties" developing in the tank. However, it is still possible to have an above ground system doing the same job. They tend to be smaller, as it is more important to keep the water moving, to stop the build up of "nasties". So how does that help you if you have no garden. Well, there are several products on the market, that are slimline and can fit flush to an outside wall, for example, and take up little space. Of course, capacity is not great, but then there is the option (space permitting), to have more than one tank, thus increasing capacity. Ultimately, you may not be able to harvest as much rainwater as you could potentially, but something is often better than nothing. Unfortunately, without having more specifics regarding your situation, I think that this is the best answer I can give you at present. However, if you would like more information, then please feel free to contact me, and hopefully, I will be able to give more guidance. Our web address is www.viridisec.co.uk, on there is a "contact us page". I think it's great that you are looking at saving water, and I think the key thing is that we should all do as much as we can. "Every little helps!" As a well known supermarket would say!

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ksousa

ksousaComment left on: 13 January 2009 at 9:10 pm

I was born and raised in Bermuda where we primarily rely on rain water for our drinking / bathing and everything else water and found this article particularly interesting. Could you shed some more light on how this could be used for those of us without the luxury of a garden? :) The next time I go back home i'll keep an eye out for such catchments, especially in the local nurseries and such. I don't recall seeing anything of the like while I was growing up... will be interesting to learn what they're doing :)

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Barry Nutley

Barry Nutley from Viridis Energie ConsultantsComment left on: 8 January 2009 at 10:28 pm

Hi Keith. Thanks for the question. It's a great point. Typically, a suitably powered pump should be suggested by your installer/consultant, to take into consideration any points such as these, and indeed if you have a particularly large garden that you may want to irigate, then, indeed, a more powerful pump may be suggested.

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keith poulter

keith poulterComment left on: 8 January 2009 at 6:00 pm

how does rainwater harvesting get over the problem that a lot of modern cisterns need high pressure water to fill them in a reasonable time, as do washing machines?

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