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A secondary suite or basement apartment is an excellent way to provide a living space for an extended family member or create a rental suite to make extra money. However, if you build a second unit within your existing home without following regulations, you could face fines and may even have to undo the work.


The certified plumbers at Black Forest Plumbing can help take care of all your plumbing construction needs for your basement apartment or second dwelling unit in the Greater Toronto Area. Contact us today to learn more about our plumbing services and how we can help make your secondary suite a reality.

What is a Secondary Suite?

The province of Ontario defines a secondary suite as a “self-contained living accommodation for an additional person or persons… in which both food preparation and sanitary facilities are provided for the exclusive use of the occupants of the suite.” For you, this means the installation of sinks, faucets, drains, showers and toilets, which require a professional to ensure the plumbing is installed correctly. 



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Second Unit Plumbing Regulations in Ontario

The Province of Ontario has these minimum requirements for second-unit plumbing:

  • A hot and cold water supply

  • A sink, bathtub or shower, toilet, or a drainless composting toilet in the bathroom

  • A kitchen sink

  • access to laundry facilities in a shared laundry room or a separate area in the second unit

Moreover, a second unit must have a separate water shut-off valve. The valve allows plumbing work or repairs to be done in one unit without affecting water flow in the other. The law also stipulates that a qualified plumber does all the installations. 

If your additional dwelling unit is in a flood-prone area, you may also have to install a backwater valve. This valve prevents sewage from entering floor drains and plumbing fixtures during wet weather events.

If you have an independent septic system, you’ll need to check with your municipality to ensure your septic tank is big enough. You may need to upgrade your septic system to handle the extra sewage flow. 

Finally, you may consider installing a tankless water heater in your rental suite to take the pressure off your hot water supply. A tankless water heater delivers hot water immediately, and you’ll never have to worry about the tank running out of water.

Basement Apartment Plumbing

You may turn your basement into an additional dwelling unit or rental suite. At a minimum, when constructing a basement, you must follow the requirements for second-unit plumbing outlined above. However, the rules governing basement apartments in Ontario are complex and vary from one municipality to another. 


Remodelling a basement bathroom requires digging the piping and drainage into the concrete floor, tying it into the drainage system, and establishing proper drainage and venting, all complicated tasks. Building codes may require installing an ejector to pump waste away from the bathroom into the sewer system. Regulations may also specify minimum downhill slopes for drains. 


Not getting it right the first time can be costly and prevent you from using your suite. Leave it to Black Forest Plumbing to ensure all the plumbing work is up to code.

Residential Plumbing Installation in the Greater Toronto Area and throughout Ontario

At Black Forest Plumbing, our certified plumbers can handle the plumbing installation or repairs to get your secondary suite or basement apartment up to Ontario building requirements. We install toilets, appliances and hot water tanks. Contact us today to speak with one of our staff about the plumbing work on your next project.

Check Your Local By-Laws

Plumbing is just one facet of the planning and construction process. Check with your local municipality for zoning restrictions, parking rules and anything else that may prevent you from adding a secondary suite to your home. On completion, you’ll need the following documents: 

A fire certificate from your local fire authority
A certificate from the Electrical Safety Authority (ESA)
Building Permit Completion or a Certificate of Compliance from your municipal building department

Doing the construction yourself or not hiring certified professionals can result in a failure to meet building codes and may prevent you from renting out the property. 

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