You could either go to each grocery store and ask for donations of bottled water or you could do a fundraiser and buy bottled water.
Get together with a couple other groups and do a free car wash in the Church parking lot. That's right, don't charge a dime. Instead make flyers or cards that thank them for stopping by [...]
Talk to your priest about being "the" group that takes care of cleaning or upkeep of certain parts of the Church, Rectory, or Offices