Resource Guide

When Do You Need a Plumbing Permit in Ontario?

Plumbing permits in Ontario are governed by the Ontario Building Code. This guide explains which plumbing projects require a permit, which do not, and why getting a permit matters for your home's safety, insurance, and resale value.

Plumbing Work That Typically Requires a Permit

The following types of plumbing work generally require a building permit under the Ontario Building Code. This list covers the most common residential scenarios, though specific situations may vary by municipality.

• New Plumbing Rough-Ins

  Any new plumbing installation that involves running new supply lines, drain lines, or vent pipes requires a permit. This includes adding a bathroom, kitchen, or laundry room to a home, finishing a basement with a bathroom, adding a wet bar, or any project that creates new plumbing connections where none existed before. The rough-in phase (before walls are closed up) must be inspected to ensure proper pipe sizing, slope, venting, and connection methods before the work is concealed.

• Moving or Relocating Fixtures

  If you are moving a toilet, sink, bathtub, or shower to a different location within the home, a permit is required because the drain, vent, and supply piping must be rerouted. Even moving a fixture a few feet can require changes to the drain slope, vent configuration, and trap arm length that must meet code requirements. This commonly comes up during bathroom and kitchen renovations where the layout is being changed.

• Water Heater Relocation

  Moving a water heater to a new location within the home requires a permit because it involves changes to the water supply piping, drain connections, gas piping (if applicable), and venting. Replacing a water heater in the same location with a similar unit may not require a permit in all municipalities (see the section on what does not require a permit below), but relocating it always does.

• Sewer Line Replacement or Repair

  Replacing or repairing the sanitary sewer lateral, whether inside the home or between the home and the municipal connection, typically requires a permit. This includes trenchless pipe lining or bursting as well as traditional dig-and-replace methods. The permit ensures that the new pipe meets current code requirements for material, slope, connections, and cleanout access. Sewer line work is one of the most important areas where permits protect homeowners, because improper sewer connections can cause backups, contamination, and expensive damage to both the homeowner's property and the municipal system.

• Backwater Valve Installation

  Installing a backwater valve on the main sanitary sewer line requires a permit in virtually every Ontario municipality. The installation involves cutting into the main drain line inside the home, which is regulated work under the OBC. This is particularly important for homeowners applying for municipal basement flooding rebates, as most subsidy programs require a permit as a condition of the rebate.

• Adding New Fixtures

  Installing a new toilet, sink, shower, bathtub, dishwasher connection, or any other plumbing fixture where one did not previously exist requires a permit. This includes adding a second kitchen sink, installing a utility sink in the garage, or adding a bathroom in a previously unfinished space. The permit ensures proper drainage, venting, and water supply for the new fixture.

• Water Service Line Replacement

  Replacing the water service line from the municipal main to the home requires a permit and, in many municipalities, coordination with the local water department. This work often arises when upgrading from an old lead or galvanized service line to copper or plastic, which is increasingly common in older Ontario neighborhoods.

• Major Repipe Projects

  Replacing significant portions of the home's supply or drain piping, such as replacing all galvanized supply lines with copper or PEX, or replacing a cast-iron drain stack, generally requires a permit. The threshold varies by municipality, but any project that involves changing the pipe material or routing for a substantial portion of the system will typically trigger the permit requirement.

The Permit Process: What to Expect

If your plumbing project requires a permit, here is what the typical process looks like in most Ontario municipalities.

• Application and Fees

  The permit application is submitted to the local building department, usually by the plumber or contractor doing the work, though homeowners can also apply directly. The application typically includes a description of the proposed work and may require a basic sketch or plan showing the plumbing layout. Permit fees for residential plumbing work in Ontario generally range from $100 to $300, depending on the scope of the project and the municipality's fee schedule. Some cities charge a flat fee for standard items like backwater valve installation, while others calculate the fee based on the project's construction value.

• Plan Review

  For straightforward residential plumbing work (a single backwater valve installation, for example), the plan review may be completed at the counter on the same day or within a few business days. For more complex projects, like a full basement rough-in with multiple fixtures, the review may take one to two weeks. The building department checks that the proposed work meets Ontario Building Code requirements before issuing the permit.

• Inspection

  Once the permit is issued and the work is underway, one or more inspections are required. For new plumbing installations, a rough-in inspection is done before walls or floors are closed up, so the inspector can see the pipes, connections, venting, and slope. A final inspection may be done after the project is complete. The homeowner or contractor schedules the inspection with the building department, typically with 24 to 48 hours notice. If the work passes inspection, the permit is closed. If it does not, the inspector will note the deficiencies, and the work must be corrected and re-inspected.

• Permit Closure

  A closed (or finalized) permit means the work was inspected and approved. This is important documentation for the homeowner. An open permit, meaning the work was started but never inspected or signed off, can create problems when selling the home, making insurance claims, or doing future renovations. Always ensure your plumber schedules the required inspections and that the permit is properly closed.

Common Scenarios and Whether a Permit Is Needed

Here are some of the most common plumbing scenarios Ontario homeowners encounter, along with general guidance on whether a permit is typically required.

• Replacing a toilet with a new toilet in the same spot

  No permit required. This is a like-for-like fixture replacement with no changes to the plumbing connections.

• Moving a toilet to the other side of the bathroom during a renovation

  Permit required. The drain, vent, and supply piping must be rerouted to the new location.

• Installing a backwater valve

  Permit required in virtually all Ontario municipalities. This involves cutting into the main sanitary drain line.

• Adding a bathroom to a finished basement

  Permit required. This is new plumbing installation with new drain, vent, and supply connections.

• Replacing a kitchen faucet

  No permit required. This is routine fixture maintenance.

• Replacing an old galvanized water service line with copper

  Permit required. This is a change in pipe material and involves the main water service connection.

• Fixing a leaking pipe joint in the basement

  No permit required. This is a repair to the existing system.

• Replacing a sewer lateral from the house to the street

  Permit required. This is major drainage work that must meet current code standards.

• Replacing an existing sump pump

  Generally no permit required for a straightforward pump replacement in an existing pit.

• Converting from a tank water heater to a tankless unit

  Permit likely required. Changing the type of water heater involves different venting requirements, gas piping changes (if applicable), and potentially different water connections. Check with your local building department.