Officials with the Bangor Water District, who now own the standpipe, said their fall tour is the most popular because of the beautiful leaf peeping views.
Before the event was even over, they had more than 1,400 people come through.
Once people climb the 100 steps to the top, they can take in downtown Bangor and plenty of fall foliage.
"It's a landmark for the city of Bangor," said Patrick Smith, the construction development supervisor for the Bangor Water District. "Great views when you get up there all around. On a good, clear day you can see [Mount] Katahdin."
The standpipe is still used to provide water to Bangor and holds 1.75 million gallons of water.
It's open to the public four times a year, and there will be another tour in December.