CSO FAQs

If we separate the sanitary sewage and stormwater, and catch debris from stormwater run-off, would that make our waterways safer and cleaner?

Not completely. Our water will still be polluted from sources upstream of our City and State. That's why it's important that this be recognized as a regional watershed problem that will require interstate cooperation.

Why do you say we need to eliminate 85% of the CSO events? Why not 100%?

To capture the remaining 15% of CSO, the price would be beyond any possible benefits. EPA estimates that $44 billion will be needed to limit municipal CSO discharges nationwide to 4-to-6 times per year (85% capture), and over $200 billion would be necessary if CSO discharges are to be eliminated entirely. Even the EPA recognizes that 100% control of CSO throughout the US will be very expensive and does not require it.

What about the cost? Who pays?

CSOs are a shared City, County and State concern and responsibility for the cost of improvements should be a shared solution. Wilmington is working to comply with Clean Water Act requirements without sending local residential monthly sewer bills skyrocketing. In addition, the City is applying for grants available from the EPA.

Shouldn't Wilmington have been working on this problem earlier?

Contrary to what you may have heard, much has been done already.

In 1997, at a cost of $30 million, Wilmington expanded its wastewater treatment plant, boosting the capture and treatment of combined stormwater and sanitary flow from 49% to 70% (one of the highest capture rates in the nation).
In 1999, Wilmington's Long Term Control Plan was created.
In addition, the City has implemented a CSO Crew, dedicated to keeping all CSO structures free of obstructions. This action alone will prevent about 65 overflows per year.
The City implemented EPA’s Nine Minimum Controls.

What are EPA’s Nine Minimum Controls?

Wilmington has already implemented the Nine Minimum Controls required by EPA; they are:

1.	proper operation and regular maintenance programs for the sewer system and the CSOs;
2.	maximum use of the collection system for storage;
3.	review and modification of pre-treatment requirements to assure CSO impacts are minimized;
4.	maximization of flow to the City’s treatment works for treatment;
5.	prohibition of CSOs during dry weather;
6.	control of solid and floatable materials in CSOs;
7.	pollution prevention;
8.	public notification to ensure that the public receives adequate notification of CSO occurrences and CSO impacts; and
9.	monitoring to effectively characterize CSO impacts and the efficacy of CSO controls.

<<Back