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Rainwater harvesting - New build

  • 25-12-2023 8:58pm
    #1
    andyd12
    Registered Users, Registered Users 2 Posts: 380 ✭✭


    I am strongly considering a rainwater harvesting system for a new build. As such:

    https://www.graf.info/en-ie/rainwater-harvesting.html

    Water within the area from the group water scheme or a well is quite hard. As a plumber, I know the trouble this causes mechanically and visually.

    I plan on having the system do everything except the drinking water. Water will be fully treated using pre-UV & UV filtration. Backup will provided from group water scheme or a well during prolonged dry spells. 3k for a 5000l tank. Also available in 1500, 3000 & 7500 litre

    What are peoples experience here?



Comments

  • #2
    mickdw
    Registered Users, Registered Users 2 Posts: 23,435 ✭✭✭✭mickdw


    I'm surprised it's not a building regulation requirement at this stage.

    Seems like a good all round idea.



  • #3
    scottser
    Registered Users Posts: 764 ✭✭✭scottser


    Unfortunately I don't have anything technical to contribute except to say that any sort of future-proofing is money well spent.

    If its a new build, is there a reduction in the development levy payable to the local authority, given that there is less wear on infrastructure?



  • #4
    tom1ie
    Registered Users, Registered Users 2 Posts: 10,683 ✭✭✭✭tom1ie


    Just wondering but if you had reverse osmosis and charcoal/ceramic filters included off a separate line from the water that goes through the pre filtering from the rain water tank- why couldn’t you have drinking water also?



  • #5
    andyd12
    Registered Users, Registered Users 2 Posts: 380 ✭✭andyd12


    https://www.boards.ie/discussion/comment/121535831#Comment_121535831

    The development levy is currently being waived by government to encourage home ownership. However, group water schemes don't come under this. It's not massive money to connect if needed.

    I think the wear aspect would be hard to quantify



  • #6
    listermint
    Registered Users, Registered Users 2 Posts: 34,085 ✭✭✭✭listermint


    Bury it if you can. But it's a too idea..no idea why it couldn't be drinking water if filtered and treated tbh.



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  • #7
    Shoog
    Registered Users, Registered Users 2 Posts: 5,983 ✭✭✭Shoog


    We had a terrible GWS so we built our own concrete tanks at around 16k LTRs. That was our primary source of water for over a decade. We would run out of water once every few years - usually in early spring after a sustained dry period. We were a family of four. If you want this to be your primary water source then 5k LTRs would be extremely marginal.

    We never drank the water and never treated it in any way but it tested good other than a slight bit of fungal spore contamination from leaves in the gutters.

    UV is expensive to operate as the bulb lasts about a year and cost quite a bit - then they draw a bit of electricity.

    As to the question of reverse osmosis for drinking water, they generally need to be followed by a salt injector to put minerals back into the water - otherwise the taste is virtually undrinkable.



  • #8
    johndoe99
    Registered Users, Registered Users 2 Posts: 1,882 ✭✭✭johndoe99


    you'll have no trouble filling it with the weather we have in this country.



  • #9
    andyd12
    Registered Users, Registered Users 2 Posts: 380 ✭✭andyd12


    https://www.boards.ie/discussion/comment/121535963#Comment_121535963

    Quite possibly. I haven't looked the required filtration in massive depth to achieve a drinking water standard.

    Thinking loosely, if a bird was dead in the gutter, would the mentioned filtration be sufficient to kill all antibodies?

    Graf have been quite receptive to using rainwater for the whole house(except drinking) provided UV filtration is used.

    However, another company were not so keen, saying it should only be used for washing machines & toilets. Trying to plumb a house in this way with different cold feeds for different utilities becomes messy.

    I think, filter the rainwater as best possible. In times of drought, some type of 3-way valve to use the group water scheme or a well as a back up.

    Drinking water from the group scheme or well on the RO unit(undersink) treatment to improve quality/taste.



  • #10
    tom1ie
    Registered Users, Registered Users 2 Posts: 10,683 ✭✭✭✭tom1ie


    AFAIR I’ve seen you tube videos of charcoal+ ceramic filters coupled with UV light to provide drinking water for RWH setups- but again that’s YT and possibly not what a professional specialist would recommend nor the local council accept!



  • #11
    Shoog
    Registered Users, Registered Users 2 Posts: 5,983 ✭✭✭Shoog


    Unfortunately if you are already on a GWS there are no grants available for your own water supply.



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  • #12
    mike_2009
    Registered Users, Registered Users 2 Posts: 533 ✭✭✭mike_2009


    I'm going with a 5,000 litre concrete tank - only taking water from the rear roof, as the front roof in my case is much smaller and mixes with the driveway aco drain - more likely to be contaminated from car wash soaps, oil leaks, chemicals from pressure washing driveway etc.

    Plan to use only for washing machine and flushing loos though. There is a top up option but it's one way, mains to the rainwater tank. The main hot/cold system will be potable but I'm lucky I'm on the mains supply (public) so no issue there except it's medium hard.

    You could use a big sand filter / Reverse Osmosis or Distillation to make the water drinkable but operational costs and having to test the water regularly to ensure it's safe would also be mandatory in my view, I wouldn't want to risk my families health, even with shower water. Think about those warning signs when you're abroad on holidays, don't drink the water / brush your teeth with it!!



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