You are a small business and your operations generate waters that you discharge into the same sewer that carry your domestic sanitary wastewaters from your bathrooms (from toilets, sinks, or showers).  Do you need a separate permit from the municipality for the waters specific to your business operations?  If you meet one of the following scenarios, you would be considered a Significant Industrial User (SIU) and would therefore need to apply for a permit from the municipality receiving your domestic sanitary wastes. 

Scenario 1 – What type of business do you own/operate?

By federal regulations at 40 CFR 403.6 and 40 CFR Chapter I, subchapter N, certain businesses are subject to specific monitoring requirements for specific discharges prior to discharge to a municipal sewer.  If you are a business that discharges wastewaters subject to these specific federal regulations, known as Categorical Pretreatment Standards, you would be considered a Categorical Industrial User (CIU) and you would be required to obtain a permit. 

Scenario 2 – How much wastewater is your business generating? 

There are specific volumes of wastewater that will require you to obtain a permit, independent of the types of wastewater being generated.  By federal regulation at 40 CFR 403.3(v), which is equivalently adopted via local code by most municipalities, you would need a permit if you are discharging greater than 25,000 gallons per day (gpd), excluding the domestic sanitary discharges.  Though federal regulation, and the equivalently adopted local code, provides an exception for noncontact cooling and boiler blowdown wastewaters, it would be prudent to check with your municipality about the need for a permit if you exceed the 25,000 gpd threshold with these specific wastewaters, not including domestic sanitary discharges. 

Scenario 3 – What are the characteristics of your discharges? 

By federal regulation at 40 CFR 403.3(v), and via local code from most municipalities, you would be required to obtain a permit if your discharges exceed five percent of the municipality’s Publicly Owned Treatment Works (POTW) organic and hydraulic loadings.  Because most POTWs are designed to process organic (and hydraulic) loadings in the millions of pounds (and gallons) per day, it is unlikely that your business would be applicable to this scenario.  An exception may exist if you are one of the few dischargers to a municipality’s POTW.  If you think this is the case, it would be a good idea to discuss the need for a permit with your local municipality. 

Scenario 4 – Could your discharges adversely affect POTW operations?

Per 40 CFR 403.3(v), and vial local code from most municipalities, you would also require a permit if your discharges could result in an adverse impact to the local municipality’s POTW operations.  Given the size of most POTWS (in the millions of gallons per day of hydraulic capacity), it is unlikely that you would be applicable to this scenario, though it would be a good idea to discuss the need for a permit with your local municipality if you are not sure. 

If you are still not sure after reading these scenarios, a call to your local municipality never hurts.