Mould and indoor air quality (IAQ) issues can affect your health and comfort in any Ontario rental home. As a tenant, knowing your legal rights and understanding what actions you can take is essential to protect yourself and your loved ones. This guide explains your options if you're facing problems with mould, persistent dampness, or poor air in your Ontario rental unit, all under current province laws.

Understanding Mould & Indoor Air Quality Problems

Mould is a type of fungus that thrives in damp conditions and can appear on walls, ceilings, bathrooms, or behind furniture. It often looks like black, green, or white spots, and is sometimes associated with a musty odour. Poor indoor air quality can result from mould, as well as inadequate ventilation, high humidity, tobacco smoke, or building materials.

• Common health issues: allergies, asthma, headaches, cough, skin and eye irritation
• Possible causes: plumbing leaks, roof leaks, poor ventilation, flooding, or condensation

Even hidden mould can impact health, especially for children, seniors, and those with compromised immune systems.

Your Rights and Landlord Responsibilities in Ontario

Your landlord is legally responsible for maintaining your rental unit in a good state of repair, fit for habitation, and complying with Ontario's Residential Tenancies Act, 2006^[1]. This includes fixing problems that can lead to or cause mould and ensuring safe air quality.

• Structural repairs to prevent moisture
• Fixing plumbing or roof leaks
• Ensuring proper ventilation (e.g., in bathrooms or kitchens)

Under Ontario's Residential Tenancies Act, 2006, tenants are responsible for keeping their unit clean and promptly reporting maintenance issues.

If you want more details about tenant and landlord duties, see Obligations of Landlords and Tenants: Rights and Responsibilities Explained.

What to Do if You Find Mould or Suspect IAQ Issues

1. Document the problem: Take clear photos and notes (dates, locations, severity, health impacts).
2. Notify your landlord in writing: Be specific about what you found, where, and when. Keep copies.
3. Allow a reasonable time for repairs: Landlords generally need time to investigate and fix the issue.

If your landlord does not fix the problem after you've informed them, you have the right to take further action.

How to Escalate: Filing a Complaint and Seeking Repairs

Should your landlord fail to address mould or indoor air quality, you can:

• Contact your local municipal property standards office or bylaw department to request an inspection.
• Apply to the Landlord and Tenant Board (LTB), the tribunal that resolves residential tenancy disputes in Ontario.

Relevant Official Forms

• LTB Form T6: Tenant Application about Maintenance
  Use this form if your landlord has not repaired mould or resolved IAQ issues after written notice.
  How to use: Attach documentation of the issue and copies of your communications. File the form with the LTB.
  Download Form T6 from the Ontario LTB

You can request remedies such as an order for the landlord to repair the problem, a rent reduction, or compensation for damages related to poor air quality or mould.

Municipal Inspections

Your local property standards or public health department may inspect and order your landlord to make repairs if they find a health or safety violation. This is often a useful step before or during an LTB application.

Prevention and Routine Maintenance

Preventing mould or IAQ problems is a shared responsibility. As a tenant, you can:

• Use kitchen and bathroom fans to vent moisture
• Avoid blocking air vents or windows
• Report leaks, condensation, or water damage promptly

Landlords must perform regular building maintenance and promptly repair leaks or ventilation systems. For common renter concerns, see Health and Safety Issues Every Tenant Should Know When Renting.

Know Your Rights: Legal Backing

Ontario's Residential Tenancies Act, 2006 protects your health and safety as a renter. The Act is enforced by the Landlord and Tenant Board (LTB). For a broader overview, read Tenant Rights in Ontario.

FAQ: Mould & Air Quality Issues for Tenants

1. Is my landlord required to fix mould problems in my Ontario rental unit?
   Yes, landlords must maintain rental units in a habitable state, which includes resolving mould and any conditions that may affect your health and safety.
2. Can I withhold rent if my landlord won’t fix a mould or air quality issue?
   No, you cannot withhold rent. Instead, file a T6 application with the Landlord and Tenant Board and continue paying rent.
3. How long should my landlord take to fix mould after I report it?
   Landlords should act promptly, but the exact time may depend on the severity. If the landlord is delaying unreasonably, you can contact local bylaw or apply to the LTB.
4. What if I get sick from mould in my rental?
   See a doctor, document your symptoms, and let your landlord know. You may include this evidence if you apply to the LTB for compensation or repairs.
5. Can I move out if the air quality is unsafe?
   If the unit is unfit for habitation and not repaired, you may have the right to move out. Seek legal advice or contact the LTB before taking this step.

Conclusion: Key Takeaways

• Both tenants and landlords share responsibility for clean, safe rental units.
• Report mould and air quality issues in writing and document everything.
• Use official channels—municipal inspectors and the LTB—if repairs are not made.

For more legal details and a safe rental home, remember to Find rental homes across Canada on Houseme anytime.

Need Help? Resources for Tenants

• Landlord and Tenant Board (LTB) – Information, forms, and dispute resolution for tenants and landlords in Ontario
• Contact your local city or municipal property standards/bylaw office for rental inspections
• Public Health Units – For urgent health hazards or advice on air quality concerns
• Community Legal Clinics – Free advice on tenant rights and how to apply to the LTB
• Tenant Rights in Ontario – Quick overview of all provincial rights and support links

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1. Ontario Residential Tenancies Act, 2006: Read the Residential Tenancies Act
2. Landlord and Tenant Board: Ontario LTB Website
3. LTB Forms for Tenants: Official Forms Download
4. General health info: Ontario Ministry of Health – Air Quality and Your Health

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