What is a spring house. Is that a fancy word for outhouse, or is it a large storage shed?
Actually , it is a little of both; an outbuilding which shaded and protected an underground aquifer.
Basically, its a shed over an underground spring.
The early settlers used the uprising water spring as a refrigerator to keep food longer, and chilled bottled liquids
since it ran cooler than surface water, and kept a constant temperature since the source is subterranean.
The amount of water flowage was irrelevant, what mattered is its' consistency as a year round drinking water source, and temperature control.
Similar to a root cellar for consistent temperature, except that a root cellar is dry food storage.