Blog · Waterloo

Who can install a gas water heater in Waterloo? TSSA certification and the rental licence form

In Waterloo, as everywhere in Ontario, a gas water heater may only be installed, repaired or removed by a person holding a TSSA gas technician certificate, working for a company registered with TSSA as a fuels contractor. A handyman, a plumber without a gas certificate, or the homeowner cannot legally connect the gas side, and for landlords the certified technician's signature is part of keeping the City's rental licence.

Last updated October 24, 2026 · Reviewed by the Waterloo Water Heater team

Who is allowed to install a gas water heater in Ontario?

Only a certificate holder under Ontario's fuel industry regulation. A gas water heater is a fuel-fired appliance under the Technical Standards and Safety Act, and O. Reg. 215/01 says no person shall perform the functions of a certificate holder without first having obtained a certificate from the director. The certificate that covers residential water heaters is the G.2: the regulation states that a G.2 holder may install, inspect, alter, purge, activate, repair, service or remove a natural gas or propane appliance that has an input of 400,000 Btuh or less, which takes in every residential water heater made.

A G.3 is a trainee-level certificate. Under the regulation a G.3 holder may carry out a limited list of tasks on a gas appliance only under the supervision of a G.1, G.2 or domestic appliance certificate holder, and only where that supervisor has documented and signed off the trainee's skills. So a G.3 arriving alone to swap your tank in Laurelwood is not what the rules contemplate.

Is the technician enough, or does the company need something too?

Both are required. TSSA states that most fuels regulations call for contractors in Ontario to be registered by TSSA, and that registered fuels contractors are responsible for hiring the appropriate certificate holders for the type of work they perform. When a job is subcontracted, TSSA says both contractors have to meet the registration and certification requirements. TSSA has prosecuted on exactly this point: in a 2023 case it publicized, the sole director of a plumbing and heating company, himself a certified G.2, pleaded guilty under the Act after sending an uncertified employee to install a natural gas water heater in a home. The lesson TSSA draws is that the public should hire only registered contractors for the installation, service and inspection of fuel-fired appliances.

TSSA also runs an annual awareness campaign about what it calls trunk slammers: unregistered or uncertified workers who work out of their vehicles with cheaper labour and materials, whose work TSSA never audits. Its advice is to hire only TSSA-authorized individuals, and it notes that inadequate installation of fuel-burning appliances and poor maintenance are the major contributing factors in fuels incidents.

How to check before anyone touches the gas line

1. Ask the company for its TSSA fuels contractor registration number and look it up in TSSA's Find a Registered Fuels Contractor tool on tssa.org. A company that cannot produce the number is not registered.
2. Ask the technician to show the certificate. It is a TSSA-issued card naming the holder and the certificate class. For a water heater you want to see G.2 (or G.1, which covers everything a G.2 does and more).
3. If anything seems off, call TSSA. TSSA invites the public to call 1-877-682-8772 to verify a technician's qualifications.
4. Expect a leak test and a tag. A certified installation ends with the gas connections tested and, where new piping has been run, a pressure test tag on the piping.

The contractor we book for Waterloo is a TSSA-registered fuels contractor and sends G.2 technicians for every gas replacement and repair. You are welcome to ask for both numbers before the visit.

What about the City of Waterloo, and what about electric tanks?

The City of Waterloo does not license gas work; that is provincial. The City's permit checker says that replacing a plumbing fixture with the same type in the same location does not need a building permit, and that basement work which adds plumbing or creates a second unit does. The page does not name water heaters, so a like-for-like tank swap sits with the no-permit fixture replacements and a new heater for a secondary unit is part of a permitted job. The Building Department at 519-747-8712 confirms your case. The gas connection itself is never a City permit; it is the technician's certification.

An electric tank has no gas side, so the TSSA rules do not apply to it. It does have a 240-volt circuit, and that connection is the Electrical Safety Authority's territory. Work on the circuit is a licensed electrical contractor's job, and connecting a new tank to an existing, correctly sized circuit is what a plumber or water heater installer does. Condos in Uptown Waterloo on electric tanks fall here.

Landlords: the gas appliance form and the rental licence

The City of Waterloo licenses low-rise residential rentals and renews the licence annually, and the City notes that new rental licensing requirements start July 1, 2026. The licence application package requires a gas or oil fuelled appliance inspection form that must be completed by a Class 1 or Class 2 gas fitter, carrying the contractor's TSSA registration number, one form per unit, or a signed declaration that the unit has no such appliances. A gas water heater is a gas-fuelled appliance. For an owner with six tanks across several addresses in Northdale and the university district, the practical approach is one scheduled visit per property for the inspection form, a flush and any repairs, timed outside exam periods and move-in week. The annual flush and maintenance service here is built around that. The City's licensing office confirms exactly which appliances its form covers for your property.

Why the rule exists. A gas water heater that is connected with a leaking fitting, vented into a chimney that cannot carry its exhaust, or set up with the wrong orifice for the fuel can leak gas or carbon monoxide into the house. Those failures do not announce themselves. The certification system is how Ontario ensures that the person who made those connections was trained and tested on them, and the registration system is how TSSA can audit the company afterwards. It is also what an insurer will ask about if a gas appliance is ever implicated in a loss.

What this means for your quote

Any quote for gas water heater work in Waterloo should come from a company that can give you its TSSA registration number on request and send a G.2 to do the work. If a price seems far below the others, ask who is doing the gas connection and what certificate they hold. The Waterloo water heater cost guide explains what moves the price in a legitimate quote, and you can request a quote here from the contractor we book, with the certification question already answered.

Sources

• O. Reg. 215/01: Fuel Industry Certificates - Government of Ontario
• Contractor Registration and Certification - TSSA
• TSSA Cautions Ontario Homeowners Against Hiring Fraudulent Fuels Workers - TSSA
• Check if you need a building permit - City of Waterloo
• Rental housing licence application package - City of Waterloo