The vast majority of sewer systems are built to take advantage of gravity, with sewer lines sloping downward to convey waste to a treatment plant. Although lift stations and force mains can be used when water must be moved uphill, slope is a critical consideration for the design and maintenance of a sewer system.

When sewer systems work, they’re largely invisible to the public. Wastewater flows, unseen, through pipes from homes, businesses and industries to treatment plants, where it is cleaned and returned to the environment. 

But standing pools of water and foul odor—signs a sewer is not functioning properly—are increasingly common.

The design and planning of a sewer system plays a key role in protecting our lakes, rivers and oceans—and the people and wildlife who swim in and drink from them. Treatment plants reduce pollutants, including the human waste, food scraps, chemicals and oils that accumulate in wastewater, so that it can be safely released into the environment.

Generally speaking, pump stations are used to help transport fluids from one point to another. They play an integral role in a handful of infrastructure systems, including sewers. Many sewer systems rely on pumping stations, or lift stations, to push wastewater from point A to point B, especially in cases where gravity can’t move flow from a low-lying area to higher ground. 

The importance of sewer system condition assessments is hard to overstate. Communities depend on sewer systems to carry waste, runoff and pollutants away to a place of final treatment or disposal. Sewer assessment programs can help us better maintain the infrastructure responsible for this—and PACP plays a big role in making sure that’s done consistently.

Sewer systems are made up of various components that work together to transport wastewater from homes and buildings to a facility for treatment.

Most often, water and wastewater utilities operate using a separate budget from the municipality’s general budget. And that budget is typically divided between operation and maintenance (O&M) and capital spending, with a higher portion of funds used for O&M, according to a 2020 municipal water and wastewater infrastructure funding study by H2O Insights. 

Sewer systems and septic systems serve the same general purpose: providing a means for disposal of wastewater from homes and buildings to protect communities and ensure water quality. Both systems filter out black water and gray water, as well as bacteria and pathogens before the water is reintroduced into the environment.

By simple definition, wastewater is water that’s been used. Wastewater originates from both residential and commercial sources, including toilets, sinks, showers, bathtubs, washing machines and dishwashers.

Sewer cleaning removes unwanted materials, such as non-biodegradable debris or grease and sludge build-up, from a pipe. Most sewer cleanings occur as part of a routine maintenance program, though cleaners also respond to emergency callouts for overflowing or damaged lines.