We get far too much blasted rain, and yet I pay my local (French? Spanish? Russian? -- it's called "Northumbria") water board good money for flushing my toilet.
How about
- I put a tank in my loft, which I fill from time to time from a water butt outside, using a pump.
- I route the rainwater from the tank to the toilet cistern.
- When the rainwater tank gives out, I either refill it using my pump, or I switch on a tap on my mains supply, also routed into the toilet cistern?
Cue the "you cant do that 'ere mate" brigade....
(I don't mean that as it looks: what I mean is that there are lots of people in this group who know "The Regs" better than most of us, and will be able to give me a reason not to bother starting!
John
p.s. I tried an ultra-crude mock-up of this plan a couple of years ago, by filling our bath with rainwater, then using a bucket to flush the bog. Apart from anything else, the rainwater smelt bad (in this volume)
There's a new swimming pool near here; opening tomorrow, which allegedly harvests all the rainwater from the roof to top up the swimming thing. It'll be interesting to see how much 'extra' water is needed - after all, there'll be showers etc...
On Wed, 16 Apr 2008 13:59:38 +0100 someone who may be jal wrote this:-
It is perfectly possible to use rainwater for all uses. That is after all what is used in the mains water system.
However the longest journey starts with a single step, for flushing the toilet it might be a good idea to pump it through a filter to take anything relatively large out.
Having done that you may want to do more. What follows is a suggestion of where you might get some ideas. It might be worth putting in provision for some of them, to make things easier if you do adopt some of these ideas later.
A little while ago I went round Earthship Fife . This is a visitor/exhibition centre which is not connected to any external services. Electricity comes from hydro (10m head onto a small turbine), wind and PV panels, which all charge up batteries. From this they run computers, lights and the most important item, the kettle.
Water comes from the roof. This goes into a 1000 litre drum via coarse gravel filters. From there it is pumped by a pressure activated pump through a couple of filters. Drinking water also goes through a UV filter. Hot water is produced in an "unvented" cylinder using immersion heaters which are part of the system to absorb excess electricity.
Having run out of the sink, the water runs through the plants in the solar buffer area (you can just about see these plants in the photograph on the home page).
The water is then pumped back to the toilet (a fairly standard toilet, though with a three setting variable flush system).
From there the water is taken to a greenhouse, which has to be 10m away from the dwelling in Scotland. There the solids are broken down and the plants irrigated. Any excess water in the greenhouse is transferred to a bed outside the greenhouse.
Earthships were started in the USA, often in desert or semi-desert areas. This one was built along the same lines as an experiment to see what works and what doesn't work so well in a different climate. The lessons learnt are the fairly obvious ones that water is not so important in Scotland, but heat is more important. Many of the ideas can be adapted to other sorts of building.
Some of these concepts are more suited to a rural area, or buildings with a reasonably large garden, but other can be applied in built up areas.
They have an on-line shop and the Earthship Toolkit has comprehensive information on the systems should you wish to study the subject further.
Well... the sensible, as in could be used by other people not just you, approach to this is to have a system for harvesting rainwater. You install an underground tank of at least 2000 litre capacity with a pump to feed water back to the house. The tank is fed from the rainwater run off, which needs to pass through a trap to remove grit and sand. Filtering is optional but may be sensible to avoid the water becoming septic. Inside the storage tank you have a float valve which connects to the main water supply. When the tank is empty, e.g. in a long drought this will "top up" the tank from the mains so that the pump never runs dry.
If the cistern is large enough to hold two traditional horizontal- lever ballcocks, that sounds a good separation (i.e. provided they're not one of the types with a dip pipe below the water level. e.g torbeck/vertical float type valves) - however that's an inelegant solution with the need for manual changeover valves if rainwater runs low.
I thought the OP was describing T-ing the 2 supplies together into the feed to the ballcock (also needing a stopcock on each supply,) in which case I think he'd need check valves.
You could possibly have a ballcock to use mains water to top up the rainwater tank and eliminate any need to manually operate valves at all if the tank ran low - provided again back-siphonage was prevented.
I'm sure I read there's WRAS approved off the shelf hardware for rainwater loo flushing with mains top-up - but I can't remember where I read about it.
It uses a pump from a rainwater butt to top up a roof tank, but I'm sure a bit of ingenuity could fit a collection tank high enough to not need it...are there any good discrete exterior wall mounted tanks, maybe 50l or so?
In fact a long thin (horizontal) tank mounted up under the eaves might be virtually invisible, while being below the level of the gutter and above the level of the cistern - ideal! Can anybody think of anything suitable to use?
You'd need some sort of valve on the mains supply that didn't open unless the rainwater supply was empty. Hmm. And some sort of grit/sand filtering on the rainwater supply. probably.
There's info on the legal situation regarding backflow here:
Ifo at one time - quite recently - made a dual suppliy tilet, which used rainwater if it was available and mains water otherwise. However, I can't find any reference too it at their website or at their UK agents, so it looks as if it may have been dropped.
I am sure that the friendly people at the Centre for Alternative Technology will be able to tell you if it - or something similar - is still available.
Forget the whole idea. The right solution is to disable anything in the toilet cistern that limits the flush volume and to adjust the floats to maximise the cistern contents under all circumstances - not this No. 1 and No.2 nonsense.
Let the water supplier deliver what they are being paid to do.
This has more input, particularly re use of float switches rather than valves
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2 ton tank is nice but there is no fixed size requirement. The bigger the tank, the more of the time it will use rain..
Dont forget you're paying for water disposal as well as delivery, so if you discharge the rain to the waterboard you're still liable for the disposal charge.
Chaps - once again thanks so much for all the useful information so far!
Andy - Yes, I omitted the vital information that I'm on a meter (voluntarily, two years ago). I agree absolutely that the buggers (i.e. any utility service you care to name, not just water) were given a licence to print money!
Going to a meter dropped our bills dramatically, because our two kids have flown the nest. But there's another big factor at play here: that I think it's a shame to waste anything at all. Paying good money to flush the toilet (while it pees down outside) seems a terrible waste to me! I don't care that 1000 litres of good clean water only costs about
80pence[1]: waste is waste, and it's wrong. (Quaintly old-fashioned, I know!)
John
[1] Once the critical mass of 'punters' in the country are on water meters, the costs will start sky-rocketing of course ("wholesale water prices" anyone?!). And they'll also find ways to charge me for rainwater that I dare to harvest; but I might be dead by that time.
It's not old fashioned at all, it's a very modern way of thinking. It's now regarded as passe as well as anti-social to waste anything even if it costs nothing.
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