By Mark Kleinman Mark Kleinman is Sky News’ City Editor and is the man that gets the City talking in his fortnightly City A.M. column. This week he writes about the new government’s plans for water firms, housebuilders and Schroders The moment has arrived. By the time City AM readers set eyes on today’s newspaper, Ofwat, the water watchdog, will have charted a course towards the survival of Britain’s biggest water supplier – or not. Thames Water’s stark, but unsurprising, warning on Tuesday was clear: unless it can raise fresh equity in the coming months, its taps will literally run dry next M…