Mendip District Council has given the green light to plans submitted by the club for changes to Farleigh House.
The club took out a long lease on the 130-acre country estate in Farleigh Hungerford when new owner Bruce Craig bought the club in April.
Its proposals to adapt the Gothic Revival house into a mixed-use HQ and training base have now been approved with conditions, as has its bid to carry out engineering works to create a training pitch.
In addition, changes to the house’s former chapel to convert it into a gym have been approved with conditions.
Club chief executive Nick Blofeld said: "We were delighted to hear the news that we had been granted permission. This will now enable us to move the admin staff out to Farleigh over the next few weeks and then hopefully the first-team squad in early October.
"Farleigh House is a real statement of intent for the club, and to have an elite training facility and everyone in one location will be a big step forward.
"It will be fantastic to finally be able to start using it as the Bath Rugby HQ."