This is a very popular site. To avoid crowds, arrive at the well before 9:00 am.
The holy well at Lough Avalla Farm is easily accessed from a 1km long gravel farm road from the Burren National Park trailhead area. There is a car park at both ends of this road. It is not wheelchair accessible.
Please note that holy wells in Ireland are sacred sites and all are considered part of the National Trust, even if they are not being maintained. Treat them with the same respect you would any other place of worship (or a graveyard).
The well is a natural underground spring, and the farmer (Harry) keeps his cattle away from it, so it is safe to drink from. The best water is closest to the mouth of the spring, and glass mugs are provided. After drinking (as much or as little as you like), you should place a coin on the rock in the stream (but not in the stream, it's not a wishing well) and/or leave a token on the rag tree. It doesn't have to be cloth. Any small trinket will suffice to pay respect and give thanks to the spirit of the well. Another ancient tradition is rubbing a red cloth against some part of your body that needs healing, and tying it to the rag tree. Some people pour the well water on injuries, and still others leave memorial cards for departed loved ones. This holy well does not require pilgrims to pay the rounds.
This particular holy well is said to cure diabetes if you drink from it in the presence of the well three times a day for two weeks. Obviously, bottling the water and taking it home will confer no benefit beyond normal hydration.