Residential Projects Apartments / Villas / Colonies / Gated Communities It has become mandatory for all new residential projects in various state capitals to install Sewage Treatment Plants and reuse treated water for toilet flushing, car washing, etc. It is the builder’s responsibility to install the STP. As per existing norms of the Karnataka State Pollution Control Board (KSPCB), any new residential project with more than 25 units must obtain consent for Establishment (CFE) and install and operate a properly designed sewage treatment plant along with rainwater harvesting and solid waste management. Treated water must be re-used for toilet flushing, car wash, and onsite irrigation. As per Hyderabad Municipal Corporation (HMDA) guidelines, any apartment complex with more than 25 residential units must have a Sewage Treatment Plant and should reuse a minimum of 75% of treated water on site. The installation must be certified by a competent authority (Pollution Control Board). Municipal water supply connection will be provided only to those buildings that have complied with these rules. All large developments (>50 acres) must have ‘zero discharge’.