CO detectors in rental properties: obligation in Belgium
Are carbon monoxide detectors mandatory in rental properties in Belgium? Rules by Region, installation, maintenance and liability.
The carbon monoxide risk in rentals
Carbon monoxide (CO) is an odourless and colourless gas responsible for several dozen deaths per year in Belgium. Rented dwellings are particularly affected: ageing boilers, irregular maintenance, insufficient ventilation.
Sources of CO in a dwelling:
| Source | Risk | Prevention |
|---|---|---|
| Gas/oil boiler | High | Mandatory annual maintenance |
| Gas water heater | High | Ventilation + maintenance |
| Wood/pellet stove | Moderate | Chimney sweeping + ventilation |
| Portable heater (petroleum) | Very high | To be prohibited in enclosed spaces |
A landlord who lets a property equipped with combustion appliances has a safety obligation towards their tenant. Installing CO detectors is part of the mandatory diagnostics and equipment before letting.
Obligation by Region
| Region | CO detector obligation | Condition | Legal basis |
|---|---|---|---|
| Wallonia | Mandatory | If combustion appliance present | Walloon Sustainable Housing Code |
| Brussels | Recommended (quasi-mandatory) | If combustion appliance present | Brussels Housing Code |
| Flanders | Variable | Depends on heating type | Vlaamse Wooncode |
In Wallonia, the rental permit checks for the presence of a CO detector in the dwellings concerned. The absence of a detector is grounds for non-compliance.
In Brussels, the regional housing inspection (DIRL) may note the absence of a detector during an inspection. Even without an explicit legal obligation, the landlord’s liability is engaged in case of an accident if no detector was installed.
In the event of CO poisoning in a rented dwelling, the absence of a detector and/or the absence of boiler maintenance engages the landlord’s civil and potentially criminal liability.
Installing CO detectors
Location
| Placement | Recommendation |
|---|---|
| Near the boiler/water heater | Mandatory (1-3 m from the appliance) |
| Bedrooms | Recommended (detects CO during sleep) |
| Corridor/hallway | Recommended (transit area) |
| Kitchen (if gas) | Recommended |
| Attached garage | Recommended |
The detector must be placed between 1 m and 1.5 m above the floor. CO has a density similar to air and spreads evenly in the room. Avoid locations near a window or ventilation.
Choosing the detector
| Criterion | Recommendation |
|---|---|
| Standard | EN 50291 (mandatory) |
| Power supply | Lithium battery (10 years) or mains + battery |
| Lifespan | 7 - 10 years (replace afterwards) |
| Price | EUR 25 - 50 per detector |
For a standard apartment with a gas boiler, 2 detectors are sufficient: one near the boiler and one in the sleeping area.
Maintenance and cost allocation
| Action | Charged to | Frequency |
|---|---|---|
| Purchase and installation | Landlord | Before letting |
| Monthly test (test button) | Tenant | Monthly |
| Battery replacement | Tenant | Depends on the model |
| Detector replacement (end of life) | Landlord | Every 7-10 years |
| Boiler maintenance | Tenant | Annual (mandatory) |
Annual boiler maintenance is the best prevention against CO risk. Mention this obligation in the lease and request the certificate from the tenant each year.
The smoke detector is a separate obligation (fire protection) in addition to the CO detector. Both are necessary.
Record installation dates and planned replacement dates in your rental management software so you never miss a replacement.