Fun fact, while they knew there was clustering it was two deviations that drove the "proof" home it was the water pumps. One was the absence of cases at the brewery RIGHT next door, where the workers would not drink the water but beer after the fermentation process. And the case on Coventry street, that had no obvious association until the household was interviewed and the lady who had risen in station and lived there turned out to originally be from the neighborhood and insisted that water be brought from that pump because she thought it tasted better. So it was hypothesis, analysis, visualization and thick data investigation.