New General Sewer Extension Permit for Primary Residences with ADU or ARB

The Legislature has recently passed a law that effectively nullifies this General Permit – the text of the new law can be found here. This means that sewers that previously met the requirements of the General Permit are now deemed permitted and no longer require coverage under the General Permit. The Division has now shut down the general permitting program, however, if your shared sewer was eligible for coverage under the General Permit, it is now deemed permitted with no further action required. If you have any questions regarding this update, please contact Christyn Fertenbaugh at


A General Permit now exists for Accessory Dwelling Units and Accessory Residential Buildings that wish to share a common sewer line with a Primary Residence. A Certificate of Coverage (CoC) under this general permit allows residential properties to connect a new or existing Accessory Dwelling Unit (ADU) or other Accessory Residential Building (ARB) to the main residential building’s sewer line. Coverage under this general permit negates the need to apply for an individual sewer line extension permit.

Link to General Permit 

Application Materials:


Deed Restriction Template

Applicants who are not the owner of the parcel, but are applying on the owner’s behalf, must fill out the Designated Agent Authorization Form and attach it to the application. 

General Information:

An Accessory Dwelling Unit (ADU) is a single-family residence comprised of three bedrooms or fewer, constructed on the same parcel as a primary residence.

An Accessory Residential Building (ARB) is an accessory building to a primary residence, such as a garage or workshop, which may be served by a sewer lateral due to the presence of a sink, shower, toilet, or other fixture.

A Primary Residence is a residential building governed by the North Carolina Residential Building Code and may be a single-family residence or a duplex, multi-family residence. Triplex and larger multi-family residential structures, including townhome structures with three or more single-family residences, are excluded from this definition and from coverage by this general permit.

Figure: Potential sewer line configurations for Primary Residences with an ADU/ARB.

What situations qualify?

This permit can be issued for either existing structures which will be newly connected by a shared sewer line, or for new construction where either a new accessory building is joined with an existing primary residence or two such residential structures are built concurrently.

In order to qualify for coverage under this permit, the parcel containing both the primary residence and the ADU/ARB must have deed restrictions recorded in the county register of deeds office. The deed restrictions must prohibit, in perpetuity, subdivision of the parcel in any manner that separates the primary residence from the ADU/ARB.

Projects Excluded from Coverage

This permit cannot be applied to projects which require a state discharge or any other type of non-discharge permit. This permit is for the extension of sewer lines to serve a Primary Residence and an ADU/ARB only.

The following configurations of shared sewer lines are prohibited by this permit:

  • Shared sewer lines that are pressurized
  • Configurations where a pump station serves both the primary residence and the ADU/ARB
  • Shared gravity sewer lines with a diameter less than four inches

Coverage by this permit will only be granted for the sharing of a sewer line between no more than two residential buildings. This permit does not cover any accessory building which discharges more than 360 gallons per day, or which has more than three bedrooms. This permit also does not cover the sharing of sewer lines between buildings in which either is non-residential.

If your project does not qualify for coverage, you must apply for an individual sewer line extension permit. Please refer to the general permit Part I Section B to review installation requirements before completing your application.


These Frequently Asked Questions will be updated regularly as new/different questions are asked regarding this general permit. For any questions where the answer is not available below, please contact the PERCS Unit directly.


General topics:

What Activities Require This Permit? This permit is required for residential properties that wish to connect a new or existing accessory dwelling unit (ADU) or other accessory residential building (ARB) to the main residential building's sewer line.

What is the Purpose of This Permit? This general permit simplifies and expedites the process of adding an accessory building to a primary residence by negating the need to apply for an individual sewer line extension permit via the Fast Track program.

Who Can Apply for This Permit? This permit must be applied for by the owner of the property or a designated authority. If a designated authority is applying on behalf of the property owner, please fill out the necessary signature authorization form.

How Much Does This Permit Cost? Currently there are no application fees or annual fees for this general permit.

How Do I Apply for This Permit? Using the online application link, submit the required information along with supplementary documentation as necessary.

How Long Will It Take to Review My Application? After receiving an application, a Certificate of Coverage will generally be issued within five business days (if the project is deemed eligible and all application materials are complete and correct.) During times of high volume, applications may take up to 30 days to review.

If I receive a Certificate of Coverage, how long will it be valid? Once issued, your coverage will remain in place as long as General Permit WQG100000 is in effect, until you submit a formal request to have it rescinded.


Application-Specific Topics:

Why do some sections of the application appear/disappear when I select different options? The application is designed to be interactive and will only show you the sections applicable to your specific situation. If you have any questions about the varying sections, please contact the PERCS Unit.

A red warning popped up when I indicated that both my primary residence and my ADU/ARB will each have their own pump station and force main. What do I do? Situations where both buildings have their own pump station and force main are excluded from coverage by this General Permit. These types of situations will require either a Fast Track Sewer Extension permit or an Alternative Sewer Extension permit. Please contact the PERCS Unit for more information about permitting your sewer system.

What if my second building is an ARB, and does not have any bedrooms. How do I fill out Section III(4) of the application? For ARBs where there are no residential bedrooms, for the purposes of calculating bedrooms/flow for this section, please assume that the sink/toilet/shower is equivalent to one bedroom. For example, a garage with a sink and toilet would be the equivalent of one bedroom/120 GPD for the purposes of the application. A workshop with a sink, toilet, and shower would be the equivalent of one bedroom/120 GPD for the purposes of the application.

The municipality I am tying onto has an approved flow reduction. May I use this flow reduction to increase the size of my ADU above 3-bedrooms? No. Part I, Section A(2)(b)(6) requires that the ADU be no larger than 3-bedrooms, regardless of previously approved flow reductions.

What do I need to do if my existing sewer line is a gravity line that is less than 4-inches in diameter? General Permit WQG100000 requires that existing gravity sewer lines that are less than 4-inches in diameter be replaced with a minimum of a 4-inch diameter gravity line from the point of connection of the line from the ADU/ARB to the sewer main. Documentation of this replacement by a licensed plumber or contractor should be provided to the Division upon request.


Legal Authority/Statute Reference: North Carolina General Statute §143-215.1; 15A NCAC 02T .011; 15A NCAC 02T .0300


Statewide Contact Information:

NC Division of Water Resources

Pretreatment, Emergency Response, Collection Systems Branch (PERCS Branch)

1617 Mail Service Center, Raleigh, NC  27699-1617

Telephone: (919) 707-3601