Watford, with midfielder Tom Cleverley often the orchestrator, dominated for long periods but failed to make a breakthrough.
The closest Malky Mackay’s side came to only their second win in six league games was when Don Cowie struck a post in the second half.
Watford felt they should have been awarded a penalty in injury time when Henri Lansbury’s effort appeared to be blocked on the line by Nicky Shorey’s arm but ref Andy D’Urso waved away the appeals.
Forest’s best chance came in the final 10 minutes when Dexter Blackstock was denied by Scott Loach.
Billy Davies’ side were fortunate to escape with a point to extend their unbeaten run to 15 matches and preserve the country’s only undefeated away record.