What is the most commonly used water supply source for a standpipe or sprinkler system?

The most commonly used water supply source for a standpipe or sprinkler system is the city main. City mains provide a reliable and readily available source of pressurized water that meets the demands of fire suppression systems in urban environments. These systems are designed with the assumption that a consistent and high-pressure water supply will be accessible in case of a fire emergency.

Fire hydrants, while they do connect to the city water supply, are not typically the primary source for a standpipe or sprinkler system since they are more often used for direct firefighting by fire service personnel rather than as a permanent water supply.

Private wells can vary greatly in water availability and pressure, making them less reliable for urban fire safety standards, where consistent water pressure is essential. Similarly, water tanks may be used in some specific scenarios, such as in buildings that lack direct access to city mains, but they are not the most commonly relied upon source due to limitations in capacity and pressure compared to the city mains.

Thus, city mains are the preferred and most commonly utilized source, ensuring that standpipe and sprinkler systems are effective in controlling and extinguishing fires efficiently.