Water represented many symbols to Father Flannery. Maybe it represented the rebirth of a baptism, or the slipping into the after life of a drowned girl needing last rights.
He had once had a wife when he was younger who had always wanted to learn to swim. Of course she never did. Sailors used to purposely not learn to swim, so it wouldn’t take them so long to drown.That wasn’t the reason she didn’t learn to swim, but it was the way she drown.
He hated the way the holy water moistened his fingers. He would have gone completely without water for the rest of his life had he not lived in England, where it rains like arks need to be built.

One day during the worst storm we had ever seen, he walked outside, and folded his umbrella under his arm. He just stood in the rain.
Water just gushed off him.

They all looked the same.
He had umbrellas for every occasion, they were all black.