What is the name of the sitcom about a mother and two daughters who
live in an apartment. What was the name of the naintenance man who
usually figured prominently in the episodes?

Hi Liberia!

I recognized the sitcom immediately as "One Day at a Time". This
program aired from 1975-1984. The name of the  maintenance man  was
Dwayne Schneider,
played by Pat Harrington Jr.

Here are a couple of  pictures of Schneider.

http://geoff.ambertower.com/images/pat_harrington.jpg

http://www.collectinghollywood.com/PHarri1.jpg

One Day At a Time

Bonnie Franklin    ....  Ann Romano Royer 
Pat Harrington Jr. ....  Duane Schneider (1975-84) 
Mackenzie Phillips ....  Julie Cooper Horvath (1975-1980, 1981-1983) 
Valerie Bertinelli ....  Barbara Cooper Royer


?Ann Romano is a recently-divorced professional trying to raise two
teen-age daughters Julie, the rebellious 17-year-old and Barbara, the
level-headed 15-year-old. The family moves into an apartment in Ann's
hometown of Indianapolis, where she found work (first as a secretary
and later as an account executive for Connors and Davenport, an
advertising agency). Ann went by her maiden name, while Julie and
Barbara kept their father's name, Cooper. The building's
superintendent, Dwayne Schneider, kept a watch over the family, while
David Kane was Ann's love interest early in the season. Plots revolved
around Ann trying to raise two daughters while retaining her own
sanity.?
IMDB
http://www.imdb.com/title/tt0072554/plotsummary


You can read more about the show and see a picture of the cast at TV Tome
http://www.tvtome.com/tvtome/servlet/ShowMainServlet/showid-1317/


Search criteria:
Valerie Bertinelli
One day at a time


I hope you find this helpful!

Best regards,
Bobbie7

Unlike seasons of many other sitcoms of that era that are now
available on DVD or VHS (such as "All in the Family," "Sanford and
Son," "The Jeffersons" and others), "One Day at a Time" does not
appear to be available for home viewing at this time.  It was,
however, a popular sitcom in its era, as evidenced by the number of
years it was broadcast on television.