TL;DR: If you manage a higher-risk building, you must report certain safety incidents to the Building Safety Regulator (BSR) within 10 working days. Section 87 of the Building Safety Act 2022 requires you to have a system for identifying, recording, and reporting these occurrences. Failure to report can be a criminal offence under section 101. This guide walks you through what to report, how to report it, and how to set up a reliable process.
Key takeaways:
- You must report safety occurrences that pose a risk of significant harm to the BSR within 10 working days
- Section 87 requires a formal reporting system -- not just ad hoc responses to incidents
- Reportable events include structural defects, fire safety system failures, and compromised compartmentation
- Failure to report is a criminal offence under section 101, carrying an unlimited fine
- A due diligence defence exists if you can show you took "all reasonable steps" to comply
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Why Mandatory Occurrence Reporting Matters
Mandatory occurrence reporting is not a bureaucratic exercise. It exists because safety incidents in higher-risk buildings -- structural failures, fire system malfunctions, compromised fire compartmentation -- need to reach the BSR so the regulator can identify systemic risks across the building stock.
The Principal Accountable Person must report safety occurrences to the Building Safety Regulator within 10 working days of becoming aware of the occurrence.
— Building Safety Act 2022, s.78
The BSR has signalled that underreporting is a significant concern. Many building managers are not recognising reportable occurrences when they happen, or are treating them as routine maintenance issues rather than regulatory events. The consequence is a gap between what is actually happening in buildings and what the regulator knows about.
For you as a building manager, the practical risk is straightforward: if something goes wrong and the BSR discovers you failed to report a known safety issue, you face criminal liability under section 101 of the Act. The good news is that establishing a reliable reporting system is manageable -- and this guide shows you how.
What You Must Report
Under section 87 of the Building Safety Act 2022, the accountable person must report occurrences that relate to the structural integrity or fire safety of the building and pose a risk of significant harm to people in or around it.
A safety occurrence is any event that causes a risk to the safety of people in or about the building, relates to the spread of fire or structural failure, and is caused by the design, construction, or ongoing management of the building.
In practical terms, reportable occurrences include:
| Category | Examples |
|---|---|
| Structural defects | Cracks in load-bearing walls, foundation settlement, concrete spalling exposing reinforcement, balcony structural concerns |
| Fire door failures | Doors that fail to self-close, damaged intumescent strips, missing cold smoke seals, failed overhead closers |
| Compartmentation breaches | Missing or degraded fire stopping around service penetrations, gaps in cavity barriers, holes in fire-separating walls |
| Active fire system failures | Sprinkler system faults, smoke ventilation malfunctions, dry riser failures, fire alarm system defects |
| External wall concerns | Cladding defects, missing cavity barriers in external walls, combustible insulation discovered during works |
The threshold is not "something went wrong." It is "something went wrong that creates a risk of significant harm." A fire door that sticks slightly is a maintenance issue. A fire door that fails to close at all on a corridor serving 20 flats is a reportable occurrence because it compromises the compartmentation strategy that protects residents.
What is NOT typically reportable
- Routine wear and tear that does not create a safety risk
- Minor maintenance issues with no fire safety or structural implications
- Near-miss events where no actual defect or failure occurred
- Issues in non-residential parts of mixed-use buildings (unless they affect the residential parts)
When in doubt, report. The BSR would rather receive a report that turns out to be below the threshold than miss a genuine safety concern.
How to Report: Step by Step
The accountable person for the building is legally responsible for establishing this system. Here is the step-by-step process for handling a reportable occurrence.
Failure to report a mandatory occurrence to the Building Safety Regulator is a criminal offence under the Building Safety Act 2022, carrying an unlimited fine.
Step 1: Identify the occurrence
The first challenge is recognising that something is reportable. This requires staff and contractors who interact with the building to understand what constitutes a safety occurrence. A concierge noticing a fire door propped open is different from a maintenance contractor discovering that fire stopping has been removed during unauthorised works -- but both may be reportable depending on the circumstances.
Practical tip: Create a simple one-page reference card listing examples of reportable occurrences. Give it to every member of staff and contractor who works on site. Make it clear that they should escalate anything they are unsure about -- it is better to over-report internally than to miss a genuine occurrence.
Step 2: Record the details immediately
As soon as you become aware of a potential reportable occurrence, record:
- Date and time the occurrence was discovered (and estimated date of the occurrence itself if different)
- Location within the building (floor, flat number, common area, riser)
- Description of what was found, including photographs
- Who identified it (name, role, contact details)
- Immediate risk assessment -- does this require emergency action right now?
- Interim measures taken to manage the risk (e.g., isolating the area, deploying temporary equipment)
The clock starts when you become aware of the occurrence, not when you finish investigating it. You have 10 working days from awareness to submit the initial occurrence notice to the BSR.
Step 3: Assess the risk
Before submitting, assess whether the occurrence meets the reporting threshold: does it pose a risk of significant harm relating to the structural integrity or fire safety of the building?
If you are genuinely uncertain, submit the report. The BSR will determine whether it meets the threshold. Filing a report that does not qualify is not an offence; failing to file one that does qualify may be.
Step 4: Submit the occurrence notice to the BSR
Submit your occurrence notice through the BSR's online submission portal. The GOV.UK guidance on submitting mandatory occurrence notices and reports details the process and required information.
Your notice must be submitted within 10 working days of becoming aware of the occurrence. Include:
- Building registration reference number
- Description of the occurrence
- Date discovered and estimated date of occurrence
- Location within the building
- Initial risk assessment
- Any interim measures taken
Step 5: Prepare for the full occurrence report
After receiving your notice, the BSR may request a full occurrence report. This is a more detailed document covering:
- Root cause analysis (why did this happen?)
- Full risk assessment (what is the ongoing risk?)
- Remedial actions taken or planned (what are you doing about it?)
- Timeline for permanent resolution
- Lessons learned (how will you prevent recurrence?)
The BSR will specify the timeframe for the full report. Keep your investigation records organised from the start -- trying to reconstruct events weeks later is difficult and produces weaker reports.
Track occurrences, deadlines, and evidence in one place -->
Setting Up Your Reporting System
Section 87 does not just require you to report occurrences -- it requires you to establish and operate a system for identifying and reporting them. The BSR will expect to see evidence that you have a functioning process, not just that you react when something obvious happens.
A reliable mandatory occurrence reporting system includes:
1. Clear escalation routes. Every person working on or in the building -- staff, contractors, managing agents -- should know who to contact if they discover something that might be reportable. A single named contact or role works best.
2. Internal reporting form. A standardised form for capturing the details listed in Step 2 above. This can be digital or paper, but digital is preferable because it creates a timestamped, searchable record.
3. Assessment protocol. A documented process for deciding whether an internal report meets the BSR reporting threshold. This should specify who makes the decision and the timeframe for doing so (e.g., within 2 working days of internal report).
4. Tracking and follow-up. A register of all occurrences -- reported and not reported -- with the rationale for each decision. This is your evidence of due diligence if your reporting decisions are ever questioned.
5. Training records. Evidence that staff and contractors have been briefed on what constitutes a reportable occurrence and how to escalate. Annual refresher training is good practice.
A real-world scenario
A resident in a 12-storey building reports a crack running across the ceiling of their hallway. Your building manager inspects and finds the crack extends through the plaster into the concrete soffit of the floor above. A structural engineer confirms the crack indicates differential settlement affecting a load-bearing element.
You have 10 working days from the point your building manager confirmed this was a structural concern to submit an occurrence notice to the BSR. The notice includes the engineer's preliminary assessment, photographs, and a description of the interim monitoring measures you have put in place (tell-tales on the crack, increased inspection frequency). The structural engineer's full report, due in three weeks, will form part of the full occurrence report if the BSR requests one.
This is mandatory occurrence reporting working as intended: a concern is identified, assessed, reported to the regulator, and managed -- all within a structured, documented process.
What Happens If You Don't Report
The consequences of failing to report are both regulatory and criminal.
Criminal liability: Under section 101 of the Building Safety Act 2022, failing to comply with your duties as an accountable person is a criminal offence if the failure involves a risk of death or serious injury. The offence carries an unlimited fine. There is no imprisonment provision for this specific offence, but the financial and reputational consequences are severe.
Due diligence defence: Section 101(4) provides a defence if you can prove you took "all reasonable steps" to comply with your duties. This is precisely why having a documented reporting system matters -- it is your evidence that you took compliance seriously, even if a specific occurrence was missed.
Enforcement action: The BSR can issue a compliance notice under section 97 requiring you to establish or improve your reporting system. Failure to comply with a compliance notice is itself a criminal offence.
Impact on your Building Assessment Certificate: Your occurrence reporting record forms part of your Building Assessment Certificate application. The BSR reviews whether you have a functioning MOR system when assessing your building. Gaps in reporting -- or a complete absence of reports when incidents clearly occurred -- will raise questions about the quality of your safety management.
Frequently Asked Questions
What is mandatory occurrence reporting under the Building Safety Act?
Mandatory occurrence reporting is a legal duty under section 87 of the Building Safety Act 2022. Accountable persons for higher-risk buildings must establish a system to identify, record, and report safety occurrences that pose a risk of significant harm to the Building Safety Regulator. An initial occurrence notice must be submitted within 10 working days of becoming aware of the event.
What counts as a reportable occurrence?
A reportable occurrence is any event relating to the structural integrity or fire safety of a higher-risk building that poses a risk of significant harm to people. Examples include fire door failures, dry riser malfunctions, compromised compartmentation, structural defects in load-bearing elements, and failures in active fire safety systems such as sprinklers or smoke ventilation.
What happens if you fail to report an occurrence?
Failure to comply with mandatory occurrence reporting duties can constitute a criminal offence under section 101 of the Building Safety Act 2022. If the failure involves a risk of death or serious injury, the offence carries an unlimited fine. A due diligence defence is available under section 101(4) if you can show you took all reasonable steps to comply.
How do you submit a mandatory occurrence report to the BSR?
You submit mandatory occurrence reports through the Building Safety Regulator's online portal. An initial occurrence notice must be filed within 10 working days of becoming aware of the event. The BSR may then request a full occurrence report with detailed information about the incident, root cause analysis, and remedial actions taken or planned.
Who is responsible for mandatory occurrence reporting?
The accountable person for a higher-risk building is legally responsible for establishing and operating a mandatory occurrence reporting system under section 87 of the Building Safety Act 2022. In practice, this means the principal accountable person must ensure staff and contractors know how to identify reportable occurrences and that internal processes capture them.
Further Reading
- Building Assessment Certificate Guide: How to Prepare Your Application -- your MOR record feeds into your BAC application
- The Building Safety Act 2022: A Complete Guide for Building Managers -- comprehensive overview of all BSA obligations
- Accountable Person Duties Under the Building Safety Act -- understanding your legal responsibilities as an AP
- Fire Door Inspection Requirements: What to Document and How to Evidence Compliance -- fire door failures are common reportable occurrences
- Building Safety Act Penalties and Non-Compliance: What You Risk and How to Stay Compliant -- understanding enforcement consequences for reporting failures
- BSA Compliance Checklist -- check your compliance across all BSA requirements
- GOV.UK: Submitting mandatory occurrence notices and reports -- official BSR submission guidance
- Section 87, Building Safety Act 2022 (full text) -- primary legislation
- Higher-Risk Buildings: Definition and Criteria -- which buildings fall under the MOR regime
- What Is a Building Safety Case? -- how MOR connects to your safety case
- Golden Thread in Practice -- MOR records as part of your golden thread
This article is for informational purposes. For building-specific advice, consult a qualified fire safety professional.
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