There are three different categories of pipes that transport water from treatment plants to a customer’s property: transmission mains, distribution mains, and service connections. Transmission mains
are larger water mains with a diameter of 16 inches or larger and are used to move large amounts of water across the city between pump stations and reservoirs. Distribution mains
are smaller than 16 inches and are used to deliver water from transmission mains to customer service connections. Service connections
are the individual connections owned by the property owner that are tapped into the distribution mains that bring water into a building or house.
The Philadelphia Water Department is in charge of maintaining the entire water distribution infrastructure up to the point of the service connection; the service connection and internal household plumbing is owned and maintained by the customer.
Learn more about customer responsibilities.