Koronisia is surrounded by water but most of it is unsuitable for human consumption, since it is briny or sea water. For the monks on the island, fresh water was a necessity and a luxury. Onoufrios was determined to solve the problem, so he started digging a well on the rocky hill, near where his present-day chapel is. The other monks ridiculed his efforts, but he had faith and prayed to the Virgin Mary to guide him. She seems to have answered his prayers for he managed to located crystalline fresh water at a depth of 12 meters. He built the well you can still see there, allowing the people of Koronisia to enjoy a constant supply of water throughout the year.