These two companies not only obtained their water from cleaner sources than the Thames , but they filtered the water and treated it until there were no obvious contaminants .
Snow concluded that the companies were not to blame for the spread of the epidemic .
These two companies not only obtained their water from cleaner sources than the Thames , but they filtered the water and treated Snow until there were no obvious contaminants .
Snow concluded that the companies were not to blame for the spread of the epidemic .