Plumbing and Septic Systems

Northumberland County reviews plans, issues permits and performs inspections for septic systems in all of our member municipalities except the Municipality of Trent Hills. We also work with all municipalities to review plans and perform inspections for plumbing in all new buildings, building renovations and additions.

Plumbing/septic updates and news

In response to COVID-19, the Government of Ontario has provided a guide for maintaining building plumbing after an extended vacancy.

View the guide

When do I need a plumbing or septic system permit?

A permit is your legal right to build. Make sure you have a permit before you start work.

Work started without a permit can lead to the work having to be uncovered/exposed, higher permit cost or legal action.

You may need to obtain a permit if you are:

  • Building a new building that has plumbing
  • Building an addition that has plumbing
  • Building secondary suites including additions to existing buildings, apartments installed within an existing dwelling and secondary suites located within a new or existing approved accessory dwelling
  • Changing the use of an existing building
  • Taking out all or part of a plumbing or septic system
  • Finishing plumbing in a basement or room
  • Changing a room to a bedroom
  • Installing or changing a plumbing system
  • Installing, changing or fixing a private septic system
  • Installing a deck
  • Installing a kitchen or bathroom cupboard with plumbing
  • Installing a lawn sprinkler or soaker system
  • Installing a pylon, roof, billboard or fascia sign with plumbing
  • Installing a commercial or industrial equipment with plumbing
  • Installing a fountain with plumbing
  • Installing or changing a backflow preventer
  • Installing a municipal water service
  • Installing a fire main or hydrant
  • Installing a sanitary or storm drain outside
  • Installing or changing a fire sprinkler system
  • Installing a stand pipe system
  • Installing a glycol system

You do not need a permit for:

  • Minor repairs to a plumbing or septic system
  • Installing a kitchen or bathroom cupboard with no plumbing
  • Changing existing plumbing fixtures in the same location
  • Installing a Class 1 septic system

How do I apply for a plumbing permit?

Please contact or visit your local municipality for all plumbing permit applications.


Payments for plumbing permits are made at your local municipality – usually as part of their building permit fee.

How do I apply for a septic system permit?

Apply online

You can apply for a septic system permit using our online Permit Portal System. Through this portal, owners are able set up a personal private account to:

  • submit and pay for applications
  • review the status of their applications
  • schedule inspections
  • view inspection results
  • track all applications from a remote location

This remote option allows contractors and homeowners to access their permit information from anywhere, and will help us move towards a paper-free septic permit process.

For instructions on how to use the portal, click the information icons (a circle icon with an 'i' in it) in the portal.

Please note: Please use the revised permit application located within the portal to prevent duplication of information.

Apply for a septic permit

Apply in-person or by email

For a seamless permit process, we encourage you to submit your permit application using our online portal however, we also accept permit applications in-person or by email.

To submit in-person or by email, please complete the permit application below and attach it to your email or print a copy and bring it to our office, located at 600 William Street in Cobourg.

Permit Application

Fees and payment

Septic system permit: $875

Tank replacement: $450

We accept payment by cheque, debit and credit card. Visit us at 600 William Street in Cobourg to pay in person.

Learn about septic systems

View the SepticSmart! booklet to learn more about your home's septic system.

When do I need a plumbing or septic system inspection?

All new construction of plumbing and sewage systems in Northumberland County (excluding sewage systems within the Municipality of Trent Hills and plumbing systems within the Municipality of Port Hope) are subject to inspection by County Plumbing and Sewage System Officials.

Plumbing inspections

Please provide two business days' notice for substantial completion of:

  • Site servicing (outside services)
    • Outside water services, sanitary and storm sewer connections prior to backfilling
    • Testing is required for all industrial, commercial, institutional and multi-residential unit and may be requested by the inspector for any other occupancy type
  • Site servicing (domestic supply)
    • Includes domestic water and fire service mains 3” and larger
    • Testing and sampling is required on all installations and the fire main must be filled using a backflow protected water supply
    • The backflow prevent must be tested prior to use and the test report submitted
  • Under slab
    • Includes interior underground storm and sanitary drains prior to backfilling
    • Testing is required for all industrial, commercial, institutional and multi-residential units and may be requested by the inspector for any other occupancy type
  • Rough-in above ground
    • Includes rough-in of drainage, waste, vents (DWV) and water pipe systems
    • Testing is required for all industrial, commercial, institutional and multi-residential units and may be requested by the inspector for any other occupancy type
  • Final
    • Includes finalizing plumbing systems, fixtures and appliances
    • Final testing is required for all prefabricated houses or at the discretion of the inspector

Septic system inspections

Please provide four business days' notice for the substantial completion of the:

  • 3 Test pits
    • Required for all sewage systems prior to permit issuance
    • The application for the permit must be submitted and complete
  • Readiness to construct the sewage system
    • To provide the inspector the ability to attend the site to discuss with the installer the installation and review the base cut for scarification
  • Final
    • Substantial completion of the installation before the commencement of backfilling

How to arrange an inspection

Call 905-372-1929 or email us.

In your request, please include:

  • Your name
  • Permit number
  • Property address
  • Type of inspection
  • Preferred inspection date (minimum of two business days' notice)

Adding to your septic system

You must apply for a Sewage Disposal System Review for any building additions, renovations or new buildings as you may be adding loading on to your septic system. You will also need a review if your local municipal building department asks you to get our comments for a new shed, pool or garage to ensure you are not constructing on the septic system.

Please note

In your application for a review, you should include a copy of the septic system permit or installation record issued when your septic system was installed and a copy of the proposed plans and existing plans. If you do not have your permit or installation record, we will search our files. If none are found, you may be required to contact a septic installer or engineer to provide a report by excavating the existing sewage system.



Search for a septic system permit

Please fill out the Sewage System Search Request Form if you need us to search our files for your septic system permit.

Please note

  • We do not have records of septic system permits prior to 1985
  • We do not have records for the Municipality of Trent Hills –⁠ please contact them directly
  • We only have records for properties that we have received an application for
  • Only the current property owner or an authorized person can request a sewage system permit search
  • If we do not find a record of your sewage system, the fee is non-refundable. 



What if there is no septic system permit?

You will need to contact an engineer or a licensed sewage system installer to diagram the location, size and type of sewage system on your property. The diagram should include the location of the leaching bed (if applicable) as well as the distances from the property boundary, wells, water features (creeks, rivers, ponds, lakes) and any buildings.

Do you have a plumbing or septic system complaint?

Please fill out the Complaint Form if you believe an individual or business has a plumbing or sewage system that is in violation of the Building Code Act. 

Please note 

  • Your identity is protected by the Freedom of Information Act
  • To receive follow-up information regarding the complaint after our inspection, please check 'request follow-up' on the complaint form


What is backflow?

Backflow is the undesirable reversal of flow of fluids, chemicals, or any other foreign material into the public drinking water system.

There are two forms of backflow:

  1. Backsiphonage - usually caused by a loss of pressure in the drinking water system
  2. Backpressure - caused by pumps, piping systems elevation, or thermal expansion from a heat source

Backflow can cause our drinking water to become polluted or contaminated. Pollution reduces the quality of drinking water. It does not create a public health hazard, but adversely affects the aesthetics of taste, odour, and appearance. However, when the drinking water is contaminated, there is concern for public health if the water is consumed. This creates a threat of illness or, in extreme cases, a fatality.


Can backflow be prevented?

Yes, the backflow of undesirable elements into the drinking water system can be prevented.


A cross-connection is a physical connection between the water supply and any source of possible pollution or contamination. By eliminating or controlling all actual or potential cross-connections, the public drinking water system will be protected within the city water main system and within buildings.

Simple plumbing changes can easily eliminate many cross-connections. However, where this is not possible, backflow prevention assemblies are installed to protect the water supply.

Location of backflow prevention

Individual (Point of Use) Protection
Individual (point of use) protection is a means by where backflow devices are installed on each potential source of backflow within the piping of a building/facility in order to protect the rest of the piping within that building/facility from potential contamination.
Zone/Area Protection

Zone or area protection is practiced within buildings/facilities where both drinking and non-drinking water piping systems exist. This type of protection may also be practiced within the distribution system of a drinking water system in order to protect individual zones or areas from possible contamination from another zone or area within the distribution system.

Premise Isolation

Backflow preventers in this instance are typically installed within the facility on the service line connection to the drinking water supply and the fire main.

*Please note that all existing ICI (industrial, commercial, institutional) and multi-residential buildings that apply for a plumbing permit to perform additions, or renovations will be required to ensure a device is installed on their domestic and fire mains and provide up to date test reports. If the building does not have the proper devices, they will be required to be installed. 

What is the County's new Backflow Prevention By-Law?

Northumberland County is developing a new Backflow Prevention By-Law to help protect drinking water in industrial, commercial, institutional (ICIs) and multi-residential buildings from cross-connection contamination within plumbing systems. This by-law will apply to all ICIs in Northumberland County, excluding those in the Municipality of Port Hope.

The County hosted two open house sessions on Tuesday, August 16th to gather feedback from the public on the proposed by-law. The feedback obtained will be used to finalize the by-law in the coming months.

To learn more, and to subscribe to receive email updates on this project, please visit the County’s consultation portal,

Do I require a permit to install a backflow preventer?


There are two ways to obtain a permit for the installation of a backflow preventer:

  1. If obtaining a plumbing permit for multiple plumbing fixtures or equipment, include the backflow preventers as well. The fee is $15.00 per device.
  2. If obtaining a plumbing permit to install one or multiple backflow preventers without new fixtures or equipment, the fee is $125.00 per device.

Please contact or visit your local municipality for all plumbing permit applications.

Do I have to test a backflow preventer upon installation?


A licensed tester is required to test a backflow preventer which has testing ports. The test is to be recorded on our test report and submitted to the plumbing inspector, the owner and the tester is to retain a copy. Once tested, the backflow preventer is required to be tagged indicating the testers contact information and the date of the test.

Do I have to retest a backflow preventer?


The Canadian Standards Association requires annual testing of backflow preventers under B64.10 This test is not mandatory by the Ontario Building Code.

A by-law must be in place in order to require mandatory annual testing. The County does not have a by-law at this time but some member municipalities do. Please check with your local municipality to determine if annual testing is required.