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How Homes are Connected to the Sewer System

A basic understanding of how your home is connected to the sewer system is important.

Every time we turn on a faucet, wash a load of laundry or flush the toilet, we generate wastewater, which is measured by a water meter connected to the main water supply line. The average person in Allegheny County uses 100 gallons per day.Fresh water enters the home through a main water supply line from the municipal water company. Inside the home, the main water supply splits into two sets of pipes: the hot water pipes lead to the hot water heater first and then follow a set of cold water pipes throughout the home supplying bathroom fixtures, such as showers and sinks as well as kitchen dishwashers and clothes washers.

As we use the water, it flows into a drain in the home and passes through a trap, a U-shaped pipe that holds water and prevents sewer gases from entering the home. If the trap becomes dry from non-use, you may notice a sewer odor; pouring water into the unused drain will refill the trap and eliminate the odor.

After passing through the trap, the wastewater continues to flow downward through large drain pipes that eventually exit the home underground at one location—through a pipe called a house lateral. The house lateral usually runs out to the street from either the front or rear of your property where it connects to the public sewer system through a Y-shaped pipe called a wye. Laterals generally have a cleanout, an opening that allows for removing any debris or obstructions that might block the flow of wastewater.

Know how the sewer system works