Section 39(14) in Tamil Nadu Combined Development and Building Rules, 2019
(14)In areas where sewage system provided by the Local body concerned is not available and(a)Where number of dwelling units exceeds 50 nos. or 2500 sq.m. of commercial area sewage treatment plant shall be provided and maintained for the disposal of the sewage within the site itself as per the designs approved by such other Technical agencies as Government may impaneled from time to time.(b)where number of dwelling units is less than 50 nos. or 2500 sq.m. of commercial area, septic tank with up-flow filters shall be provided and maintained for the disposal of the sewage within the site itself.
