“English and American A Kallenberg has donated 000 crowns for the erection of a home for aged servants”
Bode Bugle Friday, March 10, 1911
http://newspaperarchive.com/bode-bugle/1911-03-10

“There are everywhere homes for aged servants… The home for aged servants in Dresden is under the immediate patronage of the Queen. In 1892, when visited, it had accommodations for fifteen women who must be at least sixty-two years old and give proof of having been a servant before being admitted.”
http://brittlebooks.library.illinois.edu/brittlebooks_open/B...

You could use “domestic staff” or “domestic workers” instead of “servant”.
I would avoid “housemaid” – this is just one type of maid (see “Types of maid” - http://en.wikipedia.org/wiki/Maid). Furthermore, the housekeeper would be a služka, but she is higher than a maid in the hierarchy of domestic workers.