Water collector

I was digging a watermain today so a fire hyddrant could be moved 2m from a new sump being installed by another contractor. Oz hooked an abandoned gas main and this cylinder was on the bottom of the main. This would have collected the water in the gas and when someone complained about their gas supply playing up the gasman would have come along and put his syphon pump on this recepticle and pumped the water out.