Section 121(4) in West Bengal Municipal (Building) Rules, 2007
(4)The tank shall be provided with an overflow pipe which shall(a)be so located and fitted as to prevent entry of animals and insects;(b)not be connected to a drain or sewer;(c)have an open end to permit the overflow pipe to serve also as a warning pipe;(d)have to be so located that it is open for inspection by any person authorized by the Authority:Provided that, in the case of any building specified in sub-rule (2) of rule 93, the tank or cistern at ground level or below ground level is to be constructed in any space excepting fixed from open space.
