Is there a thirst here for a discussion on Rainwater harvesting?

Branz

Registered User
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What I have in mind is a discussion on the pros and cons of treating the rainwater for use beyond just the garden and car washing.
Just want to flush out any interest.

Am looking at the economics of using it for everything other than cooking/drinking.
I expect post 2016 the costs will be close to euro 1,000/pa for 2 adult/2 (non-teenager) kids.
 
I think I posted recently here on this - looking for more info on the subject. Did a bit of research on the subject and for a retrofit, it simply doesn't stack up.


I contacted two different outfits. One gave me prices for supply only - and it was a substantial amount - and that's before dealing with the headache that comes with trying to retrofit. The second guy I approached used to be involved with it - and he told me straight out, it simply wouldn't pay for itself in a domestic scenario.

Perhaps the calculation is a bit more sympathetic if it's being included as part of a new build.....?
 
Am looking at the economics of using it for everything other than cooking/drinking. I expect post 2016 the costs will be close to euro 1,000/pa for 2 adult/2 (non-teenager) kids.
I can't see that it would make economic sense. What are you going to save? maybe €2 per day? Surely there are easier ways to cut €2 from your daily spend.
 
Thanks for the replies.
Cannot argue with any of the input.
In terms of numbers
I have got estimates for a 3,500l tank
Civil works: 500
Hardware 3,500, including commissioning
Connecting in: 500

This is for a concrete tank, there seems to be pros and cons for concrete v plastic.

For what its worth:
two adults here went through 41 cm (41,000 l) in 6 months from 5th Dec 13 to 5 May 14
No gardening in that.
Thats 112 l/day per head, I think the norm is c. 150l/day per adult
 
Would it be cheaper to recycle your "grey" water, from the washing machine, say, into a roof tank reserved for flushing toilets? There is no need to have drinking water for flushing and that has to be a major usage of water.
 
You are correct about the flushing being a main use of water.
A problem with grey water is you need a holding tank of some kind to allow the sludge to settle.
The plumbing also need to be A1 to make sure there is no risk of cross contamination through back-flow etc.
Its also clear from here:
http://www.irishtimes.com/news/cons...eview-details-sought-by-irish-water-1.1865800
and other sources that we are going to be billed, in due course, for sewage/grey-water etc, based on what the metered water usage is so it may change the math.
 
The recycle water from washing machines etc will stink to high heaven, after standing for a few days it breaks down.
 
Q - it simply wouldn't pay for itself in a domestic scenario.
Kind of like the whole solar thing that kicked off a few years ago...

Only way to make it save you money is if you can spend as little as possible on some sort of system to begin with.
I have a plan for tanks in my side passage.

If flushing is the major user of water, have you done everything possible to reduce the water used per flush?

Q - holding tank of some kind to allow the sludge to settle.
Which in time will need to be cleaned out.
Shower, sink, washing machine, dishwasher.
Grey water has a lot of debris in it.

On a downer note...
Despite what we perceive the rainfall to be in this country, it actually
does not rain as much as we think.
A domestic system would want to have a fairly good capacity to work.

If you want to do some sums.
A square meter of roof will catch 1 litre of water in an hour, with average rain.
You can work out what your roof might catch in an hours worth of rain.
Then compare it to the average personal use which is about 150 litres a day.
You are wishing for a lot of rain to even make a reasonable dent it your
average consumption.

Bottom line is we use a lot of water !!
 
The recycle what from washing machines etc will stink to high heaven, after standing for a few days it breaks down.

Check your washing machine outlet pipe and the w/m soap dispenser and you will see a lot of sticky sludge so even if you do use a settlement tank to allow debris to consolidate there will be a scum left on your toilets that will not be able to clean thoroughly ...........ever.
 
Check your washing machine outlet pipe and the w/m soap dispenser and you will see a lot of sticky sludge so even if you do use a settlement tank to allow debris to consolidate there will be a scum left on your toilets that will not be able to clean thoroughly ...........ever.
Nice to see this grey matter being discussed in such black and white terms.
I agree 100%!
 
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