Its a circular problem normally. Planing permission is quite clear - no houses to be inhabited until sewers are connected. Builder races ahead and houses are ready but sewers are not connected. Builder needs money as banks are hounding him, purchasers want in because they've already been waiting so long. Builder tries to pressurise Council, Council say"on yer bike, sunshine" and on and on it goes. In fairness, Councils are pretty much on the ball ( IMO) and its over excited builders who are the problem.
Sit tight and wait is the answer.
mf