Water in Ireland runs from soft enough that you'll never descale a kettle to hard enough to kill an immersion element in a few years. What decides it is the ground the water passes through before it's collected. Lakes and rivers fed off granite, shale and bog stay soft. Water that runs through limestone, which lies under most of the midlands, picks up calcium and magnesium and comes out hard. Here's a typical figure for each county we have good data for, what the numbers mean, and where a water softener is worth it.
Quick answer
- Very hard (300 mg/L and over): Meath, Kildare, Louth, Laois, Offaly, Carlow and Kilkenny, plus east Galway, Ennis and north Fingal
- Hard (200 to 299): Westmeath, Wexford, Limerick, Tipperary, Waterford, Cork city, north Dublin and the Monaghan borehole towns
- Moderately hard (100 to 199): Galway city, Killarney, Sligo town and parts of west Dublin
- Soft (under 100): south Dublin, Wicklow, Cavan town, Letterkenny and Connemara
How water hardness is measured
Hardness is measured in milligrams per litre (mg/L) of calcium carbonate. There's no single official scale, and councils band it in different ways, so we use one simple scale across our whole site, including our hardness checker:
| mg/L | Classification | What you'll notice |
|---|---|---|
| Under 100 | Soft | Little or no scale. Soap lathers easily |
| 100 to 199 | Moderately hard | Some scale in kettles over time, spots on glass |
| 200 to 299 | Hard | Kettles fur up quickly, scale on taps and shower screens |
| 300 and over | Very hard | Heavy scale, shorter life for heating elements and appliances |
Hard water is safe to drink, and there's no limit for hardness in the Irish drinking water regulations. Calcium and magnesium aren't harmful. The problem with hard water is limescale, not health.
Water hardness by county
These are typical figures for the main public supplies in each county, rounded. Within one county, a town on lake water can be soft while the next town on a borehole is hard, so check your own Eircode before you buy anything. Tap a county name for our local page.
Leinster
| County | Typical hardness | Rating | Notes |
|---|---|---|---|
| Meath | about 355 mg/L | Very hard | Navan, Trim, Ashbourne, Kells, Dunboyne |
| Kildare | about 325 mg/L | Very hard | Naas, Newbridge, Athy. Maynooth and Celbridge get the Leixlip supply, about 200 |
| Louth | about 310 mg/L | Very hard | Drogheda, Dundalk |
| Laois | about 300 mg/L | Very hard | Portlaoise and the limestone towns |
| Offaly | about 300 mg/L | Very hard | Tullamore, Birr, Edenderry |
| Carlow | about 300 mg/L | Very hard | Carlow town, on the Barrow |
| Kilkenny | about 300 mg/L | Very hard | Kilkenny city, on the Nore |
| Westmeath | about 280 mg/L | Hard | Mullingar (Lough Owel), Athlone (Lough Ree) |
| Wexford | about 240 mg/L | Hard | Wexford town, Gorey, Enniscorthy |
| Dublin | 50 to 336 mg/L | Soft to very hard | Southside soft, about 50. Northside about 200. North Fingal about 336 |
| Wicklow | about 50 mg/L | Soft | Bray, Greystones, Wicklow town (Vartry supply) |
Dublin is the county where it matters most which plant feeds your street. See Dublin water hardness by area for the full breakdown.
Munster
| County | Typical hardness | Rating | Notes |
|---|---|---|---|
| Clare | 250 to 300 mg/L | Hard to very hard | Ennis about 300, Shannon about 250 |
| Limerick | about 250 mg/L | Hard | Limerick city, Adare, Newcastle West |
| Tipperary | about 235 mg/L | Hard | Thurles, Clonmel, Nenagh |
| Waterford | about 230 mg/L | Hard | Waterford city, Dungarvan, Tramore |
| Cork | about 200 mg/L | Hard | Cork city, Mallow. West Cork is softer |
| Kerry | about 130 mg/L | Moderately hard | Killarney |
Connacht
| County | Typical hardness | Rating | Notes |
|---|---|---|---|
| Galway | 135 to 300 mg/L | Moderately hard to very hard | Galway city about 135 (Lough Corrib). Tuam, Loughrea and Ballinasloe about 300. Connemara soft |
| Sligo | about 110 mg/L | Moderately hard | Sligo town (Lough Gill). Some local schemes, such as Riverstown, are far harder |
Ulster (Republic of Ireland counties)
| County | Typical hardness | Rating | Notes |
|---|---|---|---|
| Monaghan | 100 to 250 mg/L | Moderately hard to hard | Monaghan town and Carrickmacross about 250 (boreholes). Castleblayney about 100 (Lough Egish) |
| Cavan | about 50 mg/L | Soft | Cavan town (Lough Acanon). Kingscourt about 150 |
| Donegal | about 75 mg/L | Soft | Letterkenny |
Figures are typical values for the main public supplies, rounded. Some come from council and water services reports and some are regional estimates, so treat them as a guide. Hardness isn't a regulated drinking water parameter, so it isn't published for every scheme. We haven't listed Longford, Roscommon, Mayo or Leitrim because supplies there vary too much from scheme to scheme to give one honest figure.
Check your own address: put your Eircode into our water hardness checker. Or look in the kettle: if there's a white crust on the element within a few weeks of descaling, your water is hard enough for a softener to make a real difference.
On a private well? These figures are for public supplies only. Wells in limestone country are often harder again, and many carry iron or manganese, which will foul a softener. We arrange analysis through an independent accredited lab first, then specify the treatment. See well water treatment.
What hard water does in the house
- Kettles, showers and taps: white scale on elements, shower heads, glass and chrome, and it comes back within days of cleaning.
- Heating and hot water: scale insulates immersion elements and boiler heat exchangers, so they use more energy and fail sooner.
- Washing machines and dishwashers: scale on elements and valves, and you need more detergent to get the same result.
- Skin and hair: soap doesn't lather well, and a lot of people in hard water areas notice drier skin.
Do you need a water softener?
- Under 100 mg/L: no. Save your money.
- 100 to 199 mg/L: optional. A salt-free limescale filter may be enough, especially in a smaller home. See softener vs limescale filter.
- 200 to 299 mg/L: a softener is usually worth it, in appliance life and cleaning time.
- 300 mg/L and over: a softener is the only thing that properly stops the scale. Bigger households may need the Midi or Maxi rather than the Mini.
Prices start at €549 supply only and €899 fitted. Our water softener cost guide covers what's included and what it costs to run, or see the full range of water softeners.
Find out if your home needs a softener
Tell us your Eircode and how many live in the house. We'll tell you honestly whether a softener is worth it, and if it is, which size and what it costs fitted. No obligation.
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Frequently asked questions
Which county has the hardest water in Ireland?
Of the main public supplies, Meath is the hardest, at around 355 mg/L in Navan, Trim and Ashbourne. Kildare, Louth and north Fingal in Dublin aren't far behind. Some private wells in limestone areas are harder again.
Which parts of Ireland have soft water?
South Dublin, Wicklow, most of Cavan, Letterkenny and Connemara. In each case the water comes off granite, shale or bog rather than limestone, so it picks up very little calcium.
Is hard water safe to drink?
Yes. There's no health limit for hardness, and calcium and magnesium are minerals your body uses. If you do fit a softener, we recommend keeping the kitchen cold tap on unsoftened water for drinking and cooking. Here's why that matters.
Why do different websites give different figures?
There's no single official scale, so the same water can be called moderately hard on one site and hard on another. The figure itself also moves: supplies get blended, plants get switched, and readings change through the year. Use any county figure as a guide and check your own Eircode.
Does Uisce Éireann soften the water?
No. Hardness is a natural feature of the water and isn't treated out at the plant. If you want soft water, it has to be done in the house with a water softener.
