Mandatory Occurrence Reporting

Mandatory occurrence reporting is the duty that tells the regulator when something has gone wrong, or nearly has. It runs through both halves of the regime: principal designers and principal contractors operate it during construction, and principal accountable persons operate it in occupation. The reporting threshold is high, and the commonest failure is not knowing where it sits.

The threshold is high, and that is the point

A safety occurrence must be reported where it has caused, or would be likely to present a risk of:

• the death of a significant number of people, or
• serious injury to a significant number of people, meaning injury requiring immediate hospital treatment, or causing a permanent or irreversible disabling condition

Two things follow from that wording. It captures risk as well as incident, so a defect discovered before anything happens is reportable if it would be likely to present that level of risk. And it is not a general defect log: most maintenance findings will not meet the threshold, and reporting everything would be as much a failure of judgement as reporting nothing.

The judgement itself is the hard part, and it is exactly the kind of decision where the competence of the person making it becomes material.

What counts

Structural failure	Spread of fire or smoke
Total or partial collapse	Failure of compartmentation between areas
Defective building work	Failure of automatic fire prevention systems such as sprinklers or foam
Unexpected material failure relating to load bearing	Failure of fire-fighting equipment such as dry or wet risers
Discovery of structural defects affecting load-bearing capacity	Failure of automatic opening vents or smoke extraction
	Failure of fire doors and seals
	Inappropriate installation, or performance failure, of fire safety products

During design and construction the fire limb covers fire safety generally. In occupation it is framed around the spread of fire or smoke.

A notice and a report are two different things

	Notice	Report
When	As soon as you can	Within 10 calendar days of the safety occurrence being identified
Contains	Contact details, building address, the date it was identified, a brief description, and the immediate safety actions taken	The notice reference number, building registration or building control application references, organisation details, incident details, timeline, parties affected, remedial actions, and supporting documentation
Purpose	Tell the regulator quickly that something has happened	Tell the regulator what happened, why, and what you did

The ten days run from identification, not from the occurrence. A defect present for years but identified last Tuesday starts the clock last Tuesday. That is worth being clear about internally, because the date something was identified is a fact your own records will evidence one way or the other.

Both are submitted to the Building Safety Regulator through its online service.

Operating the system

The principal accountable person must operate a single system for the registered high-rise residential buildings they are responsible for. The system has to do three things: receive reports, enable prompt assessment of them, and get a notification to the regulator inside the ten day window where the threshold is met.

Who reports into it differs by phase. During construction it is designers and site workers. In occupation it is residents, accountable persons and building users, which is a much broader and less controllable population.

Residents have to be able to find it

For occupied buildings the principal accountable person should publish a policy covering what to report, how to report it, what response to expect and how data will be handled under GDPR. Guidance is explicit that it must be easily available and accessible to residents, including display in building lobbies, with alternative formats and languages where necessary.

A reporting system residents cannot find is not a reporting system. This is also where the duty meets the residents’ engagement strategy, and the two should be consistent with each other rather than written separately by different people.

Why this gets assessed

Information about the mandatory occurrence reporting system is one of the things the regulator looks at when assessing a building assessment certificate application, alongside the safety case report, the residents’ engagement strategy, live compliance notices and confirmation that building information is being provided.

There is also a connection worth noting: making a mandatory occurrence report is one of the triggers for reviewing your residents’ engagement strategy. A report should therefore move three things, not one: the occurrence record, the safety case report where the risk picture has changed, and the engagement strategy review.

Wales records, then reports to two authorities

The Welsh Act splits the duty across two sections, and the structure differs from England.

Under section 38, the principal accountable person for an occupied category 1 building must establish and operate an occurrence recording system. Its defined purpose is to enable the accountable persons for the building to comply with section 39, and it does two things: receives and records information about incidents or situations connected with building safety risks, and gives that information to the accountable persons.

Under section 39, reporting runs to the building safety authority and the fire safety authority, rather than to a single national regulator.

Section 38(5) reserves the detail to Welsh regulations, which may specify which incidents are covered, who information is received from including residents and accountable persons, how it is received and recorded, how it is assessed, and how systems are reviewed. Those regulations do not yet exist, so the operational detail of the Welsh regime is genuinely unknown rather than merely unpublished.

Common questions

Is a mandatory occurrence report the same as a RIDDOR report?

No, and one does not discharge the other. They have different thresholds, different recipients and different purposes. An event can require both, one, or neither, and each should be assessed on its own terms.

Do we report a defect nobody has been hurt by?

Potentially yes. The test captures risk as well as harm, so a discovered structural defect affecting load-bearing capacity, or a compartmentation failure, can be reportable even though nothing has happened yet. The question is whether it would be likely to present a risk of death or serious injury to a significant number of people.

When does the ten days start?

From the date the safety occurrence was identified, not the date it arose. They are calendar days, not working days.

Do we need a separate system for each building?

No. A principal accountable person operates a single system covering the registered high-rise residential buildings they are responsible for. It still has to work at building level, so residents in each building must be able to find it and use it.

Does reporting an occurrence count against us?

A system that has never produced a report in a large or ageing portfolio invites the question of whether anyone is looking. Reports evidence a working system. What matters to an assessor is what happened next: whether the occurrence was assessed, what changed as a result, and whether the safety case argument was updated.