Sewers Spell Success for Sussex County

An overabundance of bacteria pollution in the Bays can cause swimmers to experience gastrointestinal issues or infection.

Sussex County, DE — In Sussex County, over 29,000 septic systems have been switched to central sewerage over the last 30 years, a change that will improve the long-term health of the county’s waterways.

It’s no secret that the population in Sussex County has swelled in the past decades, a change that has concentrated many new homes along sensitive waterways. Along with this influx of people comes the need to safely and adequately treat an increasing amount of waste.

Onsite wastewater treatment and disposal systems, commonly called septic systems, are a large source of nutrient pollution to the Inland Bays. Conventional septic systems are only built to last between 12-20 years and many of the on-site septic systems in the Inland Bays watershed are close to or exceeding their lifespan. As these systems begin to age, the potential for failure increases and they can leach nitrogen, phosphorus — and even harmful bacteria — into the groundwater which flows the Bays. Half of the 26 monitoring stations in the Inland Bays do not meet the standard for nitrogen and phosphorus concentrations. Excess nutrients from runoff cause an overabundance of algae and murky water, which depletes oxygen killing fish and seagrass and reduces essential fish habitat. An overabundance of bacteria pollution in the Bays can cause swimmers to experience gastrointestinal issues or infection. Summer samples show that most tributary sites exceed the safe swimming standard for bacteria more than 75% of the time, demonstrating that these areas are frequently unsafe for recreation.

The Delaware Center for the Inland Bays aims to reduce this problem by implementing a Pollution Control Strategy (PCS) which calls for the conversion of onsite septic systems to central sewers that are more effective at treating pollution and more reliable.  Sussex County’s recently approved budget includes over $40 million dedicated to sewer improvement and expansion projects. The County will spend $21 million to upgrade 713 homes located along Herring Creek, a tributary that drains into Rehoboth Bay. In total, the County is working on upgrading 1,536 homes and has plans to upgrade an additional 373 homes. One future project will upgrade 120 homes in Joy Beach, costing approximately $5.5 million.

Project partner and County Engineer, Hans Medlarz, explains: “Sussex County proudly carries forward the long-standing tradition of providing central sewer service to the region to improve the water quality of the Inland Bays .” Connecting houses to central sewer will reduce nitrogen loads to local waterways by over one million pounds per year. That’s the nitrogen-removal equivalent of 100 thousand bags of 10-10-10 fertilizer, a common source of nitrogen pollution that harms the Inland Bays.


Between 2011 and 2016, the equivalent number of 6,813 single family homes were connected to central sewer, and the PCS goal for septic conversion was far surpassed.

The Center would like to extend a special thank you to Sussex County, who has been integral in making these changes. The Inland Bays are a treasure to Sussex County and provide outdoor recreation opportunities, jobs, and scenic beauty. Sussex County will continue to fund projects that convert on-site septic systems to central sewer in the coming years and is currently working on six new sewer projects.

Thank you, Sussex County, for helping us to protect the Bays!

The Delaware Center for the Inland Bays is a non-profit organization established in 1994, one of 28 National Estuary Programs. With its many partners, the CIB works to preserve, protect and restore Delaware’s Inland Bays, the water that flows into them, and the watershed around them.