Industrial Pretreatment Program FAQs

What are prohibited discharges?
Prohibited discharges are defined in Section 4.1.4 of CWS Water and Wastewater Policy manual. These discharges consist of pollutants that are not treatable by the wastewater treatment plant, have negative impacts on CWS infrastructure and treatment processes, as well as have the potential to negatively impact the Charleston Harbor.

Is my waste considered Industrial Waste?
If your waste is not of residential wastewater characteristics, then, yes your waste is considered industrial.

What is an Industrial Pretreatment Permit?
An Industrial Pretreatment Permit is an official document invoking local, state, and federal rules and regulations to a significant industrial user (SIU) or a categorical user (CIU).

Do I need a Wastewater Discharge Permit?
Not every industrial discharger is required to have a permit, but all dischargers must be in compliance with CWS sewer use ordinance defined in CWS Water and Wastewater Policy Manual.  Permits are issued to the following commercial and industrial facilities:

  • Federally regulated industries (Categorical Industrial Users).
  • Dischargers with volumes of process wastewater greater than 25,000 gallons per day (Significant Industrial Users).
  • Any discharger with the potential to negatively impact the sanitary sewer system.

If you fall under these conditions, you must obtain a wastewater discharge permit or submit a wastewater discharge permit application.

If you are unsure, please fill out the Wastewater Survey form and submit to for more information.

How long does it take to obtain a wastewater discharge permit?
The permitting process takes approximately 1.5 – 4 months, depending on the completeness of the application and the complexity of the industrial processes on site.

What does the wastewater discharge permit process entail?
Complete a wastewater survey and application. Once the application is submitted to, the Environmental Resources Dept will begin its assessment of the application and will issue a draft permit. CWS staff may do on-site evaluation of the physical address to verify reported information and determine needs. The final permit will be issued following a 30-day comment period. Application fees will be invoiced after the discharger’s first permitted month.

Are there any fees associated with the permitting process?
There is a permit application fee, which is assessed with new permits and permit renewals. Additionally, there is an annual maintenance fee for pretreatment services. Please see Section 6.2 for the most current fee schedule.

What is pollution prevention?
Pollution prevention consists of many opportunities to prevent pollution. These may include minimization, reduction, recycling, elimination, and product use of lesser pollution products in the facility’s operation and clean-up.

Where can I dispose of groundwater from excavation or remediation projects?
Groundwater from remediation projects is not allowed into the sanitary sewer unless approved by Charleston Water System. Groundwater can be disposed of in the sewer after obtaining a permit from CWS Pretreatment Program.

I have an industrial wastewater discharge permit. When are my reports to Charleston Water System due?
Reports are due on the 15th day of the following month (i.e. July’s self-monitoring report is due August 15th).

I have an industrial wastewater discharge permit. What Laboratory should I use for my self-monitoring requirements?
Any lab certified by SC DHEC who use the appropriate analytical methods as defined in 40 CFR 136.

I have an industrial wastewater discharge permit and I just became aware of a permit violation. What should I do next?
If the results of the Permittee’s wastewater analysis indicate an effluent limit exceedance has occurred, the Permittee must:

  1. Inform CWS of the violation within 24 hours of awareness of result; and
  2. Repeat the sampling and pollutant analysis and submit the results of this second analysis within thirty days of becoming aware of the first violation.