Supply ,welding and installation of hdpe pipe line form RO plant to offshore outfall header. Welding of hdpe pipe from plant to shore line was carried out. HDPE pipe line for offshore installation was also welded on the beach. Underwater survey was carried out and route of the pipe line was marked. Pipe line floated to its position and precast blocks were installed which are designed for counter weight against buoyancy. Pipe line sunk at the marked position. Underwater mud lifting carried out through out pipe line route. Pre fabricated out fall header brought to shore line and floated to offshore to its position. Underwater mechanical connection of pipe line and outfall header was done by diving team. Bags filled with suitable marine material were placed on outfall header for counter weight and resistant against sea weather. Complete underwater photography and video graphy was carried out for completion report generation which was submitted to concerned authorities.