Rivnuts from Homestead. PA on 7/5/2019 4:52:03 AM:
I am not aware of a similar, comprehensive listing of water pumps per se' for the GAP as there is no common entity that oversees and maintains the GAP like the National Park Service does for the C&O. That said, there is water available at several public trailside locations along the GAP. Here's a list of locations with free water along GAP that I am aware of.
Pittsburgh Point State Park.- Fountains
Homestead Pumphouse - Restroom sinks
McKeesport Marina - Fountain
Boston Ballfield - Fountain
Dravo Campground - Pump
West Newton Visitor Center - Fountain
Cedar Creek Park Campground - Hose bib
Round Bottom Campground - Pump (Non-Potable)
Connellsville Trailside Campground - Fountain
Ohiopyle - Fountain
Rockwood - Fountain
Meyersdale Visitor Center
Frostburg - Fountain
Cumberland Visitor Center - Restroom Sinks
There may be others and I invite other travelers to augment or correct this list. Of course, water can be obtained or purchased at other commercial locations in cities along and near the trail.