Quick answer
You can end the rental, but you should not remove a rental water heater yourself in Ontario. The tank belongs to Reliance or Enercare until it is bought out or returned under their authorisation number, and disconnecting a gas appliance and capping the line is work for a TSSA-certified G2 technician. Get the return number first, have the disconnect done, and keep the drop-off receipt.
Whether you can remove a rental water heater yourself in Ontario comes down to two things you do not control: who owns the tank and who is allowed to disconnect gas. The tank is the rental company's property, and the gas work belongs to a certified technician. What you can do yourself is the paperwork, the draining once the tank is disconnected, and the trip to the depot.
The tank belongs to Reliance or Enercare until it is bought out
A rental water heater is leased equipment. Until you pay the buyout or return the tank through the company's process, it is theirs, and the agreement you signed or inherited with the house says what happens if it disappears. Removal without a return authorisation number can leave the account open and billing, and can trigger a charge for the tank itself. Enercare's own guidance for people moving house says the customer stays responsible for the rental payments until the agreement is transferred or terminated under its terms.
So the first call is to the rental company, not to a plumber. Ask for the return authorisation number, how long it stays valid, where the tank has to go and what the account-closing charges are, and ask for all of it by email. Reliance issues what it calls a Pending Return Number and publishes its drop-off locations online. The step-by-step for each provider is in leaving a Reliance rental and leaving an Enercare rental.
Why the gas disconnect is not a homeowner job
Disconnecting a gas water heater means shutting off and opening a gas line, capping it gas-tight and dealing with the vent. Ontario's fuel certificate regulation, O. Reg. 215/01, lists removing a gas appliance among the functions of a G2 certificate holder. The same regulation has a narrow exemption for a person installing or servicing an appliance in a detached house they own and live in. That exemption does not mention removal, does not reach semis, townhouses, condos or rented houses, and does not make someone else's tank yours to pull out.
The practical risks are a cap that weeps gas into the basement and a vent left open. Where the water heater shared a chimney or B-vent with a furnace, the opening it leaves has to be sealed, and the appliance that remains may not draft the way it did. A G2 technician caps the line, leak-tests the joint and closes the vent connection before leaving.
Electric rental tanks: no gas, same ownership problem
A rented electric tank has no gas line, but it sits on a 240 V circuit and it is still the rental company's property. The breaker goes off and the circuit is confirmed dead before the wiring cover comes off, and the cable ends in a covered junction box if nothing is replacing the tank that day. Electric tanks are the norm on rural lots in Kilbride, Lowville, Campbellville and Carlisle where gas mains do not reach, and some of those are rentals as well. The return process is identical: authorisation number first, then the tank goes back.
How the return works once the tank is disconnected
- Drain it fully. Run a hose from the drain valve to the floor drain and open a hot tap upstairs; an older tank on Halton or Hamilton hard water holds sediment and drains slowly.
- Tag it. Write the authorisation number and your account number on the tank where depot staff will see them.
- Move it upright with two people or a dolly. An empty tank is awkward on basement stairs, and the fittings on top are not handles.
- Take it to the company's depot inside the window you were given, or be home for the pickup if the company collects.
- Get a dated receipt that shows the serial number, and photograph the tank and its rating plate before it leaves.
- Keep that receipt until the final bill shows zero. If a charge appears months later, that piece of paper settles it.
What a licensed disconnect and an owned replacement cost
There is no published flat price for a disconnect on its own, because it depends on the venting and on whether the gas line is capped or reused; you get that number in writing before the visit. Most people are replacing the tank the same day, and an owned tank-for-tank swap runs $1,200–$2,500 installed with the disconnect of the old unit as part of the work. Before paying a buyout instead, read whether to buy out a rental tank or replace it.
ZK Mechanical's TSSA-licensed technicians disconnect rental tanks, cap or reconnect the gas and install the owned replacement in one visit across Burlington, Oakville, Milton and Hamilton. Our water heater rental buyout service lays out what to ask the provider before anything is booked, and related questions are collected under water heater answers. Call (647) 801-1252 or tell us which company's sticker is on the tank and we will quote the swap.