A goal down at the interval Rodgers, former Academy coach at Reading, saw his side concede twice in a minute in the second half to make the game safe for the Royals and keep them in second place in the table after scoring a fourth just before the end.
Several Reading players had enjoyed a brief break in Dubai on FA Cup weekend and must have wished they were still back there on a bitterly cold and frosty night, with the game only able to go head because of undersoil heating.
Reading survived an early Watford penalty claim when full-back Liam Rosenior's strong challenge sent Job McAnuff tumbling, but Watford were then grateful to goalkeeper Scott Loach for blocking Kalifa Cisse's effort after a mistake by skipper Jay Demerit.
Twenty minutes into the game Loach came to Watford's rescue again. He just got his left hand to Kevin Doyle's shot, taking the pace off the ball and allowing him to safely gather safely at the second attempt.
Then Michael Duberry got in the way of a Lee Williamson effort and saw the shot loop dangerously close to the crossbar for a corner.
The home side took the lead in the 38th minute when Rosenior's right-wing cross caused confusion in the Hornets defence. The ball found its way to Stephen Hunt who, with two touches, laid on the chance for Chris Armstrong to score his first goal in 24 appearances since joining Reading from Sheffield United.
Watford escaped a strong penalty appeal early in the second half when Jon Harley appeared to grab Cisse's arm and pull him to the ground.
Referee Andy D'Urso ignored the claim. Then Jack Cork just deflected a Stephen Hunt shot wide of the post for a corner.
Watford's next effort was a Tamas Priskin header that was straight at home keeper Adam Federici.
Reading made the game safe with two quick goals midway through the second half. Noel Hunt scored his tenth goal of the season when he turned in a downward header from Jimmy Kebe that flicked off Harley and across the face of goal.
Then Rosenior sent in a right-wing cross which keeper Loach failed to cut out and Doyle simply had to prod the ball into the net.
With the game won Reading replaced strikers Doyle and Noel Hunt with Shane Long and Leroy Lita.
With a minute to go a long ball from James Harper sent Lita clear to slide a fourth past Loach on a night when the Royals were comfortable winners.