Rainwater Harvesting & Water Charges
Ireland isn't short of rain. A harvesting system just puts what lands on your roof to work before it reaches the drain.
Rainwater harvesting is one of the simpler renewable upgrades you can make to a property — no moving parts to speak of, nothing to learn to operate, and a resource that falls on your roof for free whether you use it or not.
How a rainwater harvesting system works
Gutters and downpipes across the roof are directed into a collection tank — usually installed underground, though above-ground tanks are an option too. All gutters and rainwater drains on the property are typically routed to the same tank, so nothing that falls on the roof goes to waste. A filtration system strips out leaves, dirt and silt before the water is stored, and a pump then delivers it back into the building's pipework or out to external taps, ready to use.
How much water can you actually collect?
It depends on local rainfall and the size and pitch of your roof, but average collection is estimated at around 100,000 litres per household per year. Commercial buildings with larger, sloped roof areas collect considerably more.
Where it makes the biggest difference
Domestic mains water billing in Ireland has shifted back and forth over the years, so it's worth checking your own water provider's current charging structure rather than assuming either way. What's more consistent is that commercial and agricultural users are typically billed for mains water on a metered basis, and a lot of rural homes are on private group water schemes rather than the public mains, with their own direct running costs. In any of those cases, cutting mains or scheme water consumption has an immediate effect on the bill — and even where there's no direct charge today, a harvesting system reduces your dependence on a supply that isn't guaranteed to stay unmetered indefinitely.
What can you actually use it for?
- Domestic — toilets, washing machines, garden watering and car washing
- Farm — washing yards, dairy equipment and general machinery
- Commercial — laundry services, car washes and other high-volume water uses
Low maintenance, once it's in
Systems can be fitted in new builds or retrofitted to existing buildings. Once installed, they're low maintenance — the filtration stage does the ongoing work of keeping debris out of the tank, so there's little for the homeowner to do beyond periodic checks. It's also worth factoring in the wider picture: Donegal isn't short of rainfall, so a well-sized system spends most of the year comfortably topped up, and every litre used from the tank is a litre that didn't need to be treated and pumped through the mains supply in the first place.
See our rainwater harvesting service page for more detail, or get in touch for a quotation based on your own roof area and intended use.