Justyn Hiscock scored six times, including a hat-trick in the first quarter, to lead the Lancers to victory.
The Eastridge sophomore finished with a season-high nine points.
Teammate Trevor Schmidt had a game-high four assists. Clay Johnson and Anthony Kimber each scored three times and had an assist for the Lancers.
Toby Loucks and Dillon McCann both finished with three goals for Waterloo.
Eastridge improves to 7-8 while Waterloo falls to 2-13