Paul,
First you must know that 'housekeeping' has pretty low profit margins to start with. Housekeeping is viewed at a low skill occupation and everybody wants a Hispanic maid that will work all day for $50 bucks - that's the background info.
We do housekeeping for about 17 apartment management companies. We also do carpet cleaning, repairs, etc. for those companies. For years we tried to stay away from apartment carpet, but as our housekeeping begain to be such a large part of our business, I finally gave-in to the dark side.
The best way to find-out is to just ask several Property Managers or their leasing agents. They will usually be glad to tell youtheir rates. Within just a few dollars, all our properties pay about the same price.