From Victorian Web:
What Kind of Staff Would a Victorian Household Have?: John Burnett, Professor of Social History, Brunel University: Victorian households built up their staffs of domestic servants in accordance with a well-understood pattern: this was based on a natural and logical progression from general functions to more specialized ones, heavily reinforced by an outpouring of literature and advice on domestic economy and household management. Domestic help began with a daily girl or charwoman. The first living-in servant would be a 'general' maid-of-all-work, almost always a young girl often of only thirteen or fourteen: the next addition a house-maid or a nurse-maid, depending on the more urgent needs at the time. The third servant would be the cook, and these three -- either cook, parlour-maid and house-maid, or cook, house-maid and nurse-maid -- then formed a group which could minimally minister to all the requirements of gentility. At this point, the first manservant would usually appear, whose duties would combine indoor work such as waiting and valeting with care of the horse or pony and carriage; J. H. Walsh placed the income level necessary for this at £500 a year in 1857.
Beyond this, the progression was not so predictable. The fifth servant might be a lady's maid or a kitchen-maid to act as assistant to the cook, or a nursemaid if there was not one already. The sixth would almost certainly be another man, acting as butler and releasing the other as a wholetime coachman or groom, which would be necessary with ownership of a four-wheeled carriage and an income of £1,000 a year. Beyond six servants, increases would follow as a result of increasing specialization -- on the male side footmen, valets, a chef and a housesteward, and on the female a housekeeper, a governess, more lady's-maids, upper and lower parlour-maids, a laundry-maid and additional kitchen- and scullery-maids. On landed estates, there would, of course, also be outside staff such as gardeners and gamekeepers, as well as many more men and boys working about the stables.
Thus, in a very wealthy town house there might be up to about twenty servants, and on a country estate up to thirty or forty. Great establishments like this could still form in the nineteenth century very much the same kind of total communities they had in the Middle Ages, highly structured, authoritarian and inward-looking, largely self-sufficient and independent of the rest of society.