This section is from the book "Ancient Legends, Mystic Charms, And Superstitions Of Ireland", by Jane Francesca Wilde. Also available from Amazon: Ancient Legends, Mystic Charms, And Superstitions Of Ireland.
The water of the sacred well must never be used for household purposes-cooking, washing, or the like. But after the well was cursed by the priest, and the tents were struck, and no pattern was held there any longer, it lost all its sanctity, and was no longer held sacred by the people, who began to fill their pails, and carry the water away home for cooking and household use ; while also they all washed their clothes down at the well, just as if no sanctity had ever been in the water.
However, one day a woman having put down a pot of water to boil, found that no amount of fire would heat it Still it remained ice-cold, as if just drawn from the well. So she looked carefully into the pot, and there beheld the Sacred Speckled Trout sailing round and round quite contented and happy. On seeing this she knew that the curse was lifted from the well, and she ran and told the priest. His reverence having seen the Sacred Trout with his own eyes, ordered it to be carried back to the well, the water of which at once regained all its sacred powers by the blessing of the priest ; and he gave the people leave thenceforth to hold their pattern there, so as they behaved themselves like decent God-fearing Christians for the future. But the water was not allowed to be carried away any more to their houses for household purposes ; the desecration of the holy water of a sacred well being strictly forbidden as dangerous and unlucky.