Boos as the travel sickness grows worse ... on-the-whistle report: Watford 5 Rotherham United 0
The Millers lost the game and yet more players to injury and also saw their boss yellow-carded on the way to their winless run on the road being extended to 21 Championship matches by Watford.
It was another tame surrender and they haven't won on opposition soil since their derby triumph at Sheffield United 368 days ago.
There were boos at half-time and full-time from travelling supporters at Vicarage Road and Taylor, who team are in the drop zone and five points shy of safety, will find his job coming under scrutiny once more.
Sam Clucas became the latest in a long line of casualties this term as he was forced out of the action before the break with what looked like a hamstring issue.
The Millers fell behind in the tenth minute when Ken Sema crossed low from the left and the unmarked Mileta Rajovic had time and space to turn a bouncing ball into the net from close range.
The home side were enjoying most of the possession and Sema brought a sharp save from Viktor Johansson when he cut inside to shoot after being released by a through ball that beat Dexter Lembikisa.
Sam Nombe's pace and physicality was asking questions of the Hornets from time to time but the half-hour mark came and went without Ben Hamer in the home goal being tested.
The Millers' jinx struck again on 33 minutes when Clucas signalled to the bench that his afternoon was over. It looked like hamstring trouble and the midfielder, who had gone down without a challenge being made on him, limped off to be replaced by Cafu.
The substitute was quickly into the action, firing in a fierce 20-yard free-kick that Hamer pushed away. Soon after he was cautioned for a foul and was followed into the book by his manager who had protested against the decision too loudly for the officials' liking.
Rotherham had made four changes to the side that had fought back in added time to earn a 2-2 draw against Ipswich Town in midweek as they switched from their usual 4-3-3 to a 3-5-2 shape.
In came Lee Peltier, Sean Morrison, Seb Revan and Jordan Hugill, with Daniel Ayala, Hakeem Odoffin, Cafu and Fred Onyedinma dropping down to a bench that was the strongest the Millers have named this season.
Record signing Nombe, having opened his account for his new club in his first home start on Tuesday, was paired up front with Hugill as Rotherham sought to score the goals that would improve their miserable record on their travels.
Christ Tiehi tried to emulate his curler against Ipswich without anything like the same effect before the visitors conceded again on the stroke of half-time.
Sema again did the damage on the left as he got the better of Lembikisa and it was that man, Rajovic, benefiting for a second time as he directed the ball into the roof of the net from point-blank range.
Within minutes of the restart, Ollie Rathbone drove towards goal for the Millers but ignored options either side of him and hit an optimistic effort wide.
At the other end, Watford were more clinical and Edo Kayembe swept a 54th-minute shot beyond Johansson to leave Taylor's men even further in arrears.
A header straight at Hamer from Ayala following a Cafu corner was Rotherham's first attempt from open play on target and the sub later sent another headed attempt wide.
The Millers made attacking substitutions but there was no way back for them and a shot high and wide from Nombe summed up proceedings.
With four minutes of normal time remaining, Tom Ince rubbed salt into the wounds with an easy finish following a Hornets break and it needed a Johansson save in stoppage time to keep the score as it was.
It was a brief respite as Matheus Martins quickly made it 5-0 with a low shot.
The boos at the final whistle were louder than they had been at the interval.
Watford (4-3-3): Ben Hamer; Ryan Andrews, Ryan Porteous, Wesley Hoedt, Jamal Lewis (Tom Ince 68); Edo Kayembe, Jake Livermore (Giorgi Chakvetadze 68), Ismael Kone (Tom Dele-Bashiru 88); Yaser Asprilla (Matheus Martins 68), Mileta Rajovic (Rhys Healey 84), Ken Sema. Subs not used: Myles Roberts, Imran Louza, Mattie Pollock, Vakoun Bayo.
Rotherham (3-5-2): Viktor Johansson; Lee Peltier (Georgie Kelly 70), Sean Morrison (Daniel Ayala 52), Cohen Bramall; Dexter Lembikisa, Ollie Rathbone, Christ Tiehi, Sam Clucas (Cafu 33), Seb Revan (Fred Onyedinma 52); Jordan Hugill (Hakeem Odoffin 70), Sam Nombe. Subs not used: Dillon Phillips, Jamie Lindsay, Arvin Appiah, Tom Eaves.
Goals: Rajovic 10, 45+4, Kayemba 54, Ince 86, Martins 90+4 (Watford).
Referee: Stephen Martin (Staffordshire).