Why isn't it raining?

Hint 1 of 12:

Haven't you heard some folk tales that explain how to create rain?

Hint 2 of 12:

Bernard will tell one of them to you if you look at the car in 1993.

Hint 3 of 12:

Washing a car makes it rain.

Hint 4 of 12:

Or in the past, washing a carriage makes it rain.  There's a carriage just
outside of the inn.

Hint 5 of 12:

All you need to do is wash that carriage, and it will rain.

Hint 6 of 12:

To clean a carriage, you need soapy water and a brush.  Everything you need
for this puzzle is available in this time frame.

Hint 7 of 12:

Get the brush and a bucket from the pantry, and then use the bucket on the
water pump to fill the bucket.

Hint 8 of 12:

For soap, you might need to call housekeeping.

Hint 9 of 12:

Pull the cord in George Washington's room and the maid will come.  And she
has soap out on her cart in the hallway.

Hint 10 of 12:

Before you can get the soap, you need to make sure that the maid is too
occupied to come out in the hallway and can't see what you're doing.