Vital statistics are sources of reliable information; and from them we can learn more of the propagation or dissemination of certain diseases through the water supply, and the relation of water to health. The cholera epidemics of Great Britain exhibit striking examples.
The following are tabulations from the Rivers Pollution Commission Report, 1874:
| LONDON. | |||
| YEAR. | CHARACTER OF WATER. | MORTALITY. | RATE PER 10,000. |
| 1832 | Polluted | 5,275 | 31.4 |
| 1849 | Very much polluted | 14,137 | 61.8 |
| 1854 | Less polluted | 10,738 | 42.9 |
| 1866 | Much less polluted | 5,596 | 18.4 |
Between the years 1849 and 1854, the water supply was much improved by removal of intakes to purer sources.
The area of intense cholera of 1866 was confined within the limits of the foul or unfiltered water supply by the East London Company; and, when notified and stopped the rate of deaths immediately decreased. It was almost exactly the area of this particular water supply, nearly if not absolutely filling it, and scarcely at all reaching beyond it.
| MANCHESTER AND SALFORD. | ||
| YEAR. | CHARACTER OF WATER. | NUMBER OF DEATHS. |
| 1832 | Used polluted water | 890 |
| 1849 | Used polluted water | 1,115 |
| 1854 | Used pure water | 50 |
| 1866 | Used pure water | 88 |
In 1851 the new supply of unpolluted upland-surface water was introduced in place of shallow wells.
| GLASGOW. | |||
| YEAR. | CHARACTER OF WATER. | NUMBER DEATHS. | RATE PER 10,000. |
| 1832 | Polluted water | 2,842 | 140 |
| 1849 | Polluted water | 3,772 | 106 |
| 1854 | Polluted water | 3,886 | 119 |
| 1866 | Pure water | 68 | 1.6 |
In 1859 the present source, Loch Katrine, was first used for water supply.