The Difference Between Sanitary Sewers and Storm Sewers

By February 24, 2020 No Comments
Storm drain on the side of an asphalt street with painted yellow line

There’s a popular misconception that all sewer systems transport all wastewater or stormwater runoff. Typically, this is not the case.

How sewage and wastewater are treated begins at the point of its origin. For example, a restaurant will have several types of waste to contend with. Sewage from the bathroom, wastewater and grease/oil products from the kitchen, and stormwater runoff from the parking lot. All three deal with different effuse in different ways.

If all three systems emptied into other citywide systems, maintenance work would be never-ending. In that respect, much of the waste material needs to be dealt with before ever reaching the main sewer and storm drain trunk lines.

A Columbia Precast Products catch basinThere are buried infrastructure components for every type of wastewater: interceptors separate the grease from the effluent water, catch basins process and trap sediment and other debris from creating blockages, and sewer manholes are in place to make sure the effluent water is transported to a septic tank or treatment facility.

Ideally, storm drain and sewer systems run side by side whenever possible to cut down on the amount of excavation. Although that’s not always possible, both systems provide the same service. Taking sewage or wastewater from one place and taking it somewhere else for treatment.

Storm Sewers

Comprised of a catch basin, manholes, containment vault, or other precast concrete detention system, storm sewers are found anywhere there is stormwater runoff to contend with. Parking lots, roads, or open spaces where standing water is a potential hazard are some examples. These storm systems are invaluable when it comes to public safety on roads, highways or freeways.

Sanitary Sewers

Manhole with Perfect Base showing channelsUsing a series of manholes and pipes, sanitary sewers are what takes the sewage from toilets, sinks, bathtubs, etc. to a treatment facility Because this waste needs to be dealt with in its entirety, the most efficient manholes are constructed using a “Perfect Base.” By casting monolithic channels into the base of the manhole, the flow line is exact, and there are fewer opportunities for debris to cause blockages.

In both sanitary and storm sewers, concrete products are the materials of choice. They are strong, built to last, and meet all local and state jurisdictions for public projects. Precast concrete vaults, basins, and manholes are popular because of their durability, ease of installation and local availability.

Precast products can be ordered well ahead of time and delivered on the day of installation. With pour in place concrete, forms need to be constructed, concrete mixed and poured, and left to harden. With precast, all of that happens within a controlled environment, taking the weather out of the equation completely.

No matter if it’s a wet well for a business park or several manholes for a new subdivision, Columbia Precast offers quick turnaround times, unmatched strength, and fast installation times. Following all ODOT and WSDOT requirements, our buried infrastructure is truly a “set it and forget it” product.