I want to reduce our metered mains water usage. So I'm
considering using rain water collected from the roof via a
huge water butt outside for flushing the downstairs toilet.
I've heard of others that have done this. I just wondered
what issues I need to think about?
Has anyone else here done this or know of any associated
Ideally if the butt runs dry then the supply needs to
switch back to mains water (either manually or
Presumably the rain water would need to be filtered to
remove any small debris that could block the ballcock
The rain water must be plumbed in so there is no
possibility of it feeding back into the mains supply.
I need to check for any associated building laws (here in
Advice or suggestions anyone on this project?
I thought about doing that, but it was ridiculously hard to comply with
the water regulations. If it were as simple as a double non-return valve
I'd have done it, too.
But instead I decided that since the loo uses /very/ little water -
about a litre on low-flush about about three on full flush that in the
unlikely event of ever emptying the butt in Slopshire's sunny climes I'd
just sling the hose into it and fill it up again. 222 litres is a lot of
flushes - and the simplicity outweighed the expected effort.
I was thinking along similar simple lines of a none-return
valve on each supply coupled into a T and feeding the loo.
With a stop tap on each feed so I could manually switch
over from mains to butt water (or turn off the water
In theory it would be quick and simple to do. I still need
to look into the French water regulations which I expect
are murky as hell (like the tap water sometimes).
Does it need to comply with the water regs if it is not directly
connected to the water supply? I mean, does connection to the sewer
mean it has to comply?
Suppose you fed the loos ONLY from the water butt and also had a ball
valve in the water butt so if it got very low it was filled form the
Yes, I think I'd need to buy a quality UK ball cock & valve
though, not one of those plastic / polystyrene French ones
which seem to fail after six months.
The thing is, most of the time the ball cock would be
submerged under several feet of water, so there would be
quite an up-force on it which could sprain or snap a cheap
David in Normandy
There is legal and assumed legal. I could find out exactly
what the legal building requirements are in France in this
respect which frankly would be complicated as my grasp of
French is not fluent yet. Or I could do as suggested which
I would *guess* would not be illegal. :-)
Just a thought. Are you likely to run into problems when the ball valve
gets covered in rainwater. They are not normally used in a mode where
there is any alternative supply. I don't know if the regs would have
anything to say about this.
One solution might be to put the valve at the top of the water butt,
opposite the overflow but engineer a long reach ball that floats at a
much lower level.
Unfortunately, I can't recall which part of Belgium was pushing the use of
rainwater a few years ago. Planning regulations required capture of
rainwater and its use prior to the use of mains water for certain uses. Woe
betide you if you were caught washing your car with mains water whilst your
rainwater tank was full!
Might be worth trying some Belgian sites - I assume the French if OK? I.d
struggle with the other!
Yes, New-Zealandish is definitely easier to understand than
French. If you think the UK income self-assessment forms
are bad you should see the ones in French!!! France has a
passion for lots of complicated forms and paperwork. Nation
of bureaucrats etc.
Here in New Zealand, I can tell you that NZ's largest water supply
company (and sewage treatment plant) takes a dim view of you putting
water that they have not supplied down their sewer system.
Rainwater is fine for washing cars and watering the lawn and garden as
long as it doesn't go down the sewer.
So if you wish to use rainwater for flushing the toilet, I suggest a
hidden pipe is best. :)
And the rainwater tank would seldom be empty. It's easier and much
cheaper to walk around and turn taps on or off a few times a year
rather than have an automatic changeover system which may go wrong.
Simpler, cheaper and more reliable, if you want to reduce your mains
water usage why not build a composting loo and use none at all? The only
water mine uses is when I rinse the collecting buckets each week after
their contents are added to a compost heap at the end of the garden and
for that I use rain water.
See <http://www.jenkinspublishing.com/garden_gallery.html .
The system certainly works in this London suburb. We've been using it
since March/April last year and I've had no complaints from neighbours.
The only briefly malodorous part of the process is the weekly emptying.
Out of consideration for the neighbours I try and ensure I empty early
morning at the weekend. Once the heap is recovered (with organic
material) there's no smell.
The only organisational problem is needing a regular supply of fine
organic plant matter to use as covering material but our garden is
organised on a wildlife-friendly basis so there's plenty of that. I did
ask tree surgeon who lives nearby whether he could supply me with fine
wood chippings on a regular basis (saving him paying to dump them too)
but after initial interest he refused. :(
If you have any questions do ask...
This would be a practical (and cheap) solution. We've got a
large garden and plenty of vegetable waste that could be
mixed with it. On the down side the Mrs would definitely
not be keen on the idea. Some ideas I can "sell" to her,
but not this one. Personally I've no problem dealing with
the poo or smell - I was brought up on a farm and also
worked on a couple of sewage farms during Summer breaks
many years ago when I was a student at college, so I've
shovelled more s**t than most people.
In use, composting toilet (in reality the part of it indoors is only a
collector) makes no more offensive smells than a flushing loo - ie when
a human is actually making their solid deposits.
Whereas with a flushing loo the flushing process removes the solids to
elsewhere (for others to deal with - not DIY at all :) with the
composting toilet collector the solids stop emanating a smell once
they're covered with shredded vegetable matter. In between use the
toilet produces a gentle aroma of woodland and is not offensive at all.
My better half was very sceptical initially and would only allow it on a
trial basis but now she's very happy we have the extra toilet available.
Joseph Jenkin's book (which is available for free download from the site
I quoted but is also available to buy in the UK) has much detail about
the possible human parasites/toxins in human faeces and how the
composting process breaks them down and renders them safe. As a result,
not only do we have an additional toilet we will also have (in another
year or so) perfectly safe to handle organic humanure to use in our
garden. No more need for chemical fertilisers either. :)
Incidentally, commercially made composting toilets seem much less
eco-friendly than the home-made one. They generally use electricity to
run a fan to remove the offensive smell (and need a pipe running up
through the roof) and dry the solids. They are also expensive to buy.
Hmmm. You've got me thinking. During the Summer months we
spend lots of time outside, usually working in the garden
or just sitting in the evening. An outside loo would be of
benefit. It can be irritating to remove muddy boots just to
come indoors to the loo. Perhaps an outdoor prototype is in
order, I doubt she'd object to that. We've certainly got
the space and no near neighbours to worry about.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.