Stormwater in our Sewer System

Stormwater entering sanitary sewers strains the wastewater system and affects your utility bill

Some people don't consider the importance of keeping storm water (rain or floodwater) out of sanitary sewers. While sanitary sewers and storm drains are often collectively called "sewers" and share some similarities, in the Beaufort-Jasper Water & Sewer Authority (BJWSA) service area they serve very different proposes.  Understanding those differences and keeping them separate helps the environment by reducing contamination through sanitary sewer overflows (SSOs) and decreases the amount of liquid that needs to be cleaned at our wastewater reclamation facilities. 

Storm drains are designed to channel rainwater away from streets, homes and communities. They direct water to nearby streams and other waterways through ditches pipes and drains. BJWSA does not construct or maintain stormwater infrastructure. Sorm drains are usually maintained by the county, municipality or your neighborhood development.

Wastewater, or sanitary sewage systems are designed to collect contaminated water from your toilets, tubs and sinks and deliver it to our water reclamation plants. Because of the source, this liquid contains germs, microorganisms and other contaminants that can threaten humans, plants and animals. Every drop of rainwater that comes in contact with sanitary sewage is considered contaminated and must be treated as sewage until it is cleaned to near-drinking water standards and can be reintroduced to our ecosystem. Stormwater entering the sanitary sewage system through inflow and infiltration (I&I) requires unnecessary capacity, treatment resources and costs.  In extreme cases, rainwater entering the sanitary system can overwhelm pumps and pipes causing sanitary sewer overflows; this is one reason it is important to avoid contact with floodwater after heavy rain.

What are inflow and infiltration?

Inflow and Infiltration (I&I) are terms used to described stormwater entry into wastewater collection (sanitary sewer) systems.

Inflow refers to water that enters the sewer system from above-ground sources, such as:

  • Direct connections from downspouts, storm drains and manhole covers
  • Surface runoff from rainfall that flows into the sewer system through other openings like defective sewer cleanout caps or foundation drains that are improperly connected to the sanitary sewer system.

Infiltration refers to groundwater that enters the sewer system through cracks, leaks or other defects in the sewer pipes, joints and manholes. The water then flows to the wastewater treatment plants for unnecessary treatment instead of filtering down into the ground. 

Inflow and infiltration can enter at several places, including the sanitary sewer system located primarily in the street and the private sanitary sewer system (called a lateral line) connecting your home to the BJWSA system.

Graphic image of how inflow and infiltration occurs on private property and in the public system

Reducing I&I

Smoke flows from a defective or improper connection at a sewer cleanoutBJWSA's sanitary sewer collection system has a maximum flow capacity of wastewater that can be handled. rainwater, which is essentially clean water, that enters the system through inflow and infiltration takes up this capacity and flows to our wastewater treatment plants for unnecessary treatment instead of filtering into the ground or entering our waterways. Inflow and infiltration can result in sewer overflows into streets and waterways, sewer backups in homes and unnecessary costs.

BJWSA has an active I&I reduction program that includes smoke detection and camera video inspection to identify defects and improper connections. When identified, we repair defects in our system and work with property owners to make them aware of needed repairs on private property.  You can learn more about our system maintenance and smoke testing initiatives here: System Maintenance | BJWSA, SC.

How you can help

Identifying and maintaining private lateral lines are the responsibility of the home or building owner. If BJWSA identifies a source of I&I into the private lateral line, it is the owner's responsibility to correct the situation. Here's how you can help:

  • Familiarize yourself with your building or home's plumbing system
  • Inspect your sewer cleanout caps - make sure the cap is on tight and the pipe has not been damaged and water cannot enter it
  • Don't plant trees or shrubs over or near where your sanitary sewer pipe is buried
  • If you find that your private line is broken, have your line repaired or replaced by a licensed contractor