Well water treatment in Co. Louth

Private wells in Co. Louth

The 2022 Census counted 5,598 Louth households on a private well or other private supply, 11.3% of the county, and another 2,387 on a group water scheme. Wells matter most in the rural middle and north: 23.0% of homes in the Ardee area and 20.5% in Dundalk-Carlingford are on a private supply, against 5.6% in Dundalk South and 0.1% in Drogheda Urban.

Household wells are classed as exempted supplies, so no one is required to test them, and Louth County Council itself warns that private supplies are at risk from germs such as E. coli O157 and Cryptosporidium. Every system we fit in Louth is specified from a lab report.

What's usually in a Louth well

Louth's water changes a lot over short distances, because the rock does. The Geological Survey of Ireland (GSI) has no county water quality report for Louth, so these figures come from its reports on individual groundwater areas.

Very hard water with manganese and iron around Dundalk

The gravels around Dundalk hold very hard water with high manganese and iron. Across 20 samples near the town, the GSI found averages of 2.05 mg/L manganese and 1.17 mg/L iron, and at Bellurgan and Ardtully hardness ranged from 136 to 710 mg/L. That spread is why one neighbour's report can't stand in for yours. Expect black staining from manganese as well as orange iron stains.

Hard water over the Drogheda and Ardee limestone

Around Drogheda and the Boyne the rock is karst limestone, with moderately hard to very hard water. Fissures and cavities were recorded in boreholes at Drybridge and Mell, and karst like this can let surface water reach a well quickly. Around Ardee it's mainly impure limestone, and the GSI's national figures for that rock average 339 mg/L, which is very hard, though individual wells vary widely.

Softer water in the Cooley hills

North and west Louth is mostly Silurian greywacke and volcanic rock, with granite taking over in the north-east around Cooley and Carlingford. Over the greywacke, where the subsoil isn't limestone, the GSI's national figures for that rock run anywhere from 5 to 481 mg/L. For granite water they range from 103 to 304 mg/L, averaging 183, so softer than the lowlands, and the GSI notes granite water can be corrosive and leach iron and manganese. Corrosive water shows as blue-green stains under copper taps.

What we usually fit in Louth

For most lowland Louth wells, the line runs in this order, with stages left out if the report doesn't need them:

1. Sediment filter to protect everything after it.
2. Iron and manganese filter, sized for the high manganese found around Dundalk, ahead of the softener so it doesn't foul.
3. Water softener for the hardness.
4. UV disinfection if the report shows E. coli or coliforms, fitted last on the main line so the water reaching the lamp is clear.
5. Reverse osmosis at the kitchen tap for drinking water, if you want it.

In the Cooley and Carlingford hills, pH correction may go in ahead of the iron filter, and a softener may not be needed. On mains water and only bothered by limescale? See our water softener page for Co. Louth instead.

The well grant in Louth

Louth County Council runs the well grant through the Rural Water section of its Environment department, under Group Schemes and Well Grants. The terms and conditions and the application form come as one combined document on that page, so read the conditions before you book any work. Have your lab report and our itemised quote ready for the application. We'll tell you which tests to order: iron, manganese, hardness, pH, nitrate, E. coli and coliforms at the very least. More in our well grant guide.