More Red Fire Hydrants Are Popping Up on the Sidewalks Just about everyone knows the old joke about why firemen wear red suspenders (to keep their pants up, of course. But red fire hydrants? If the sleek, bright red sidewalk standpipes seem to be proliferating in certain parts of Manhattan, including the Upper East Side, there are more to come. They stand out vividly compared to the standard black and silver variety. Don't expect a great hue and cry by traditionalists, though. The city says that while there may be more of them (and they are more noticeable), some New York hydrants have always been painted red. The Fire and Environmental Protection Departments explain that the red hydrants are fed by wider trunk water mains. The color also signals to firefighters that the higher-pressure hydrants should be opened more carefully. Dozens more are due to be installed by the end of the year when the next segment of the city's Water Tunnel No. 3 goes online. Construction began in 1970 on the tunnel, which will give the city a third link to its upstate water supply.