Breaking the mould in rentals: A guide for landlords

When it comes to mould in rental properties, both landlords and tenants play a role in prevention - but it’s landlords who must take the lead.

With the 1 July 2025 Healthy Homes deadline fast approaching, the stakes are higher than ever. Mould doesn’t just damage property - it can affect your tenants’ health and leave you exposed to penalties. The good news? It’s manageable with the right plan.

Here’s everything landlords need to know to keep homes healthy, compliant, and mould-free.

Why are New Zealand properties so prone to mould?

New Zealand’s damp climate and older housing stock create ideal conditions for mould - but even brand-new, well-insulated homes can be affected. The key culprit? Moisture.

Mould needs sustained moisture to grow. That can come from:

• Condensation on cold windows and walls
• Leaks in roofing, plumbing or gutters
• Everyday activities like cooking, showering, and drying laundry indoors

A 2021 study found that bedroom humidity in NZ homes exceeded 65% - the danger zone for mould - nearly half the time. Mould was most common on windowsills, ceilings, and in corners with poor airflow.

Good news is that it’s manageable

While mould is common, it’s not inevitable. With regular maintenance, proper ventilation, and clear communication, landlords can proactively address the issue.

At Property Brokers, we support over 8,000 landlords across New Zealand with regular inspections, prompt repairs, and practical advice that helps tenants reduce moisture - before mould becomes a problem.

Healthy Homes Standards are designed to help

New Zealand’s Healthy Homes Standards were created to reduce preventable issues like mould. To stay compliant, all rentals must meet the five standards by 1 July 2025:

• Heating – fixed heater capable of warming the main living room to 18°C
• Insulation – in ceilings and under floors
• Ventilation – windows that open and extractor fans in kitchens and bathrooms
• Moisture ingress and drainage – effective gutters and ground moisture barriers
• Draught stopping – blocking gaps and unused chimneys

Non-compliance can lead to fines of up to $7,200.

Need help? Talk to our team - we’ve helped thousands of landlords meet the standards and keep their rentals in top shape.

Landlord responsibilities for mould prevention

Even if your rental meets all five Healthy Homes Standards, mould can still appear - especially if tenants aren’t ventilating the home or are drying laundry inside.

Here’s what landlords are legally required to do:

• Rent out a home that’s clean, dry, and free of mould at the start of the tenancy
• Maintain the property in good repair
• Comply with Healthy Homes requirements by 1 July 2025

Best practice property management:

• Inspect the property every 13-16 weeks
• Check for leaks, clear gutters, test extractor fans
• Provide tenants with guidance on moisture reduction

When mould is reported, don’t guess - investigate.

At Property Brokers, we:

• Send a property manager to inspect and assess the issue
• Review the maintenance history and document findings
• Help determine if the cause is lifestyle-related or structural
• Coordinate repairs or professional remediation where needed

Our role is to protect your investment - and support the tenancy. That means clear communication, fast action, and fair solutions.

What tenants are responsible for

Tenants are expected to take reasonable steps to prevent mould growth:

Daily ventilation:

• Open windows each day - especially after cooking or showering
• Use extractor fans and leave them running after use
• Keep curtains open to let sunlight in

Moisture control:

• Avoid drying clothes indoors (unless vented)
• Wipe condensation from windows
• Clean minor mould spots with vinegar or diluted bleach

If a tenant notices ongoing mould even after following these steps, they should report it to their property manager. It may be a structural issue, and our team will assess and respond accordingly.

Proactive property management makes all the difference

Mould may be common, but it’s not something landlords have to deal with alone.

At Property Brokers, we offer:

• Full compliance tracking
• Regular inspections and reporting
• Fast maintenance responses
• Tenant education and support
• Local property managers who understand regional challenges

Whether you’re already working with us or just starting out, we’re here to help keep your rental dry, healthy, and compliant.

Manage your property with PB | Book a free rental appraisal

FAQs: Mould, rentals, and healthy homes

Can I charge my tenant for mould removal?

Only if their actions cause it - like drying clothes indoors with no ventilation, if it’s structural, it’s your responsibility. We’ll help assess and determine the cause fairly.

What if my tenant isn’t heating or airing the home properly?

You can’t force them, but you can educate them. Our team provides practical tips at check-in and during seasonal communications.

Do I need to upgrade insulation that passed in 2019?

Maybe. Healthy Homes Standards require specific R-values by region. If you’re unsure, book a rental appraisal, and we’ll check for you.

What if tenants keep complaining about mould after I’ve done everything?

If the home is compliant and well-maintained, it may be a lifestyle issue. We inspect, document and work with tenants to resolve it — fairly and professionally.

How can I make sure I’m compliant?

Let us handle it. Our team manages Healthy Homes compliance for thousands of properties across the country. Book a rental appraisal, and we’ll take it from there.