Derek Holmes scored his second goal in a week to settle a dour encounter at Brunton Park.
In the spring sunshine, neither side had the hunger to win despite both needing points at opposite ends of the table.
Chris Billy's Olympic-standard dive on the hour earned him a second booking and served to underline a frustrating afternoon for the home supporters.
Carlisle opened brightly but were soon kept at arm's length by the Vics who were unlucky to go into the break goalless.
Danny Mayman cracked a low shot into the corner of the net but Keiren Westwood dived well to save and Kieran Charnock saw his towering header cleared off the line with Westwood stranded.
United broke the deadlock with the first chance of the second half when Magno Vieira's shot was blocked by Andrew Ralph and Holmes was lurking to nod into the empty net.
Billy's sending off allowed Northwich back into the match and Mayman sent another drive narrowly past the post.
A smattering of bookings and fouls saw the game peter out as the Cumbrians secured a much-needed third home win in a row.