The Orchard County hit an unanswered 1-3 in the eight minutes before the break, and then reeled off four points early in the second-half to Waterford.
Waterford were not expected to push Armagh so hard and will feel they could have got even closer only for their eight first-half wides and a missed penalty by Michelle Ryan in the 45th minute.
Scorers for Armagh: L McConville (1-2), F McKenna (0-5, 2fs), S Mackle (0-3), K Mallon (0-2), M McAlinden, A McCoy (0-1 each).
Scorers for Waterford: S Dunphy (1-0), M Ryan (0-2fs), S Curran, H Landers, L Devine (0-1 each).
ARMAGH: K Daly; M Tennyson, C Morgan, S Marley; M McGuinness, N Marley, S Reel; C Malone, C O’Hanlon (capt); N Henderson, F McKenna, A McCoy; L McConville, K Mallon, M McAlinden
Subs: S Mackle for Malone (28), S Grey for McGuinness (38), L Kenny for McAlinden (45).
WATERFORD: A Jordan; N Dunphy, G Enright, M Foley; S Curran, K McGrath, G Kenneally; M McGrath (capt), E Power; L Wall, M Ryan, M Wall; A Wall, M Revins, L Devine
Subs: H Landers for Revins (19), S Dunphy for Devine (36).
Referee: M Doherty (Wexford)