After scrolling past 10 advertisements: >no one asked could definitively say why Rhode Islanders call it a bubbler

Neat.

>But there is a plausible theory.

>As you’ve probably gathered from the examples given above, when bubblers, as we know them, came out as a new technology people wanted to distinguish them from the older styles of drinking and water fountains. They had already had drinking/water fountains that they needed a cup to use – these were different. These had water that “bubbled” up and that they could drink directly from them, and they wanted language to describe that experience. And that language made its way into the mainstream, into newspapers like The Providence Journal, and, in this region, it stuck.

So we call them bubblers because that's what people started calling them because that's what they did and then people kept calling them that. But we're not certain.