The Hornets were denied what looked to be a clear goal to Fernando Forestieri that would have put them 2-0 up at Brighton and Hove Albion, and went on to drop two points at the American Express Community Stadium.
Gordon Greer's attempted clearance for the hosts seemed too late, but Watford's appeals for the goal were waved away and Andrew Crofts equalised moments later for the hosts - and the former West Ham boss was fuming with the outcome.
"There's no doubt about it, it's definitely a goal," Zola said. "Everyone has seen it apart from the referee and the officials.
"That is the disappointing part, the goal did not happen in a crowded area, there was only the player, the ball and the line and it has not been seen.
"I am disappointed because it would have given us three points.
"In a championship in which so much money is involved - they say it's £120million for the teams that go up - it (technology) would help the officials keep everything under control.
"If it is something we can use to make the game better why not? After today, I would like it to be at least considered."
Brighton manager Oscar Garcia claimed he did not see conclusive footage that the ball had fully crossed the line.
"From my position it was impossible to see," Garcia said.
"I didn't ask Gordon (Greer) about it."