The Chafetz Chaim traveled a long way to attend the wedding of one of his students, who had studied in his Yeshiva in Radin. The wedding was not in a hall but was held in the home of the bride.
Before the meal everyone went to wash Netilas yadayim - wash their hands for the meal. Out of respect, everyone made way for the Chafetz Chaim to wash first.
Before washing the Chafetz Chaim entered the kitchen for a minute. Everyone waited, understanding that the Chafetz Chaim had gone into the kitchen to check the Kashrus of the food.
He then proceeded to wash his hands. He filled the pitcher less then half way and used minimal water to wash his hands.
During the meal, the Rabbis mentioned the Gemara (Shabbos 62:) that Rav Chisda said, "I use plenty water to wash my hands and in reward Hashem blesses me plentiful too." The Chafetz Chaim understood the hint and replied, "when I entered the kitchen you all thought I went to check out the kashrus of the food. You're all mistaken. I knew the kashrus of the food here was reliable. I entered the kitchen to see who was responsible to provide the water and who had to fill the water from the well outside. (In those days there weren't faucets, people had to fetch barrels of water from outside.) I saw that it was a woman, a widow and her daughter an orphan. And I," said the Chafetz Chaim, "am not interested in receiving plentiful blessings if it is at the expense of a widow and an orphan."
Rav Yankel Galinsky once told over this story. When Rabbi Ovadia Yosef heard it, he added the following insight.
