Hygiene in the early nineteenth century was a nightmare, to put it mildly. The main issue was a lack of good clean water and a lack of good drainage systems.

From: http://www.victorianweb.org/science/health/health10.html

During the first decades of Victoria's reign, baths were virtually unknown in the poorer districts and uncommon anywhere. Most households of all economic classes still used "privy-pails"; water closets were rare. Sewers had flat bottoms, and because drains were made out of stone, seepage was considerable. If, as was often the case in towns, streets were unpaved, they might remain ankle-deep in mud for weeks. For new middle-class homes in the growing manufacturing towns, elevated sites were usually chosen, with the result that sewage filtered or flowed down into the lower areas where the laboring populations dwelt. Some towns had special drainage problems. In Leeds the Aire River, fouled by the town's refuse, flooded periodically, sending noxious waters into the ground floors and basements of the low-lying houses.

As Chadwick later recalled, the new dwellings of the middle-class families were scarcely healthier, for the bricks tended to preserve moisture. Even picturesque old country houses often had a dungeonlike dampness, as an visitor could observe: "If he enters the house he finds the basement steaming with water-vapour; walls constantly bedewed with moisture, cellars coated with fungus and mould; drawing rooms and dining rooms always, except in the very heat of summer, oppressive from moisture; bedrooms, the windows of which are, in winter, so frosted on their inner surface, from condensation of water in the air of the room, that all day they are coated with ice."