Once Rabbi Israel [Salanter] and his friend Rabbi Mordecai Meltzer were walking through the narrow sidestreets of Vilna. They stopped and entered a synagogue to join in the minchah service. Rabbi Mordecai poured a copious stream of water over his hands while Rabbi Israel [Salanter] by contrast, merely moistened his, hardly using any water at all.

Astonished Rabbi Mordecai blurted out:"Do you not, sir, observe the custom of washing before praying?"

"Indeed, I do," replied Rabbi Israel [Salanter]. "But I see here that the synagogue is frequented by a limited number of worshippers. Visitors do not usually come here. The shamash certainly intended to provide just enough water for the regular worshippers. If we waste a large quantity, the deficiency will be felt by one of the congregants. He will upbraid the shamash and withhold the few pennies he normally gives. And so we will be guilty of denying the shamash his livelihood."

-- The Mussar Movement Volume 1, Part 2, pages 219 - 220