Industrial Property Flood Risk and Drainage Due Diligence

Separate current warnings from property risk

The Department of Irrigation and Drainage’s Public Infobanjir portal provides rainfall and water-level information, while its flood-alert page publishes warning information. These are useful official starting points for understanding current conditions. A quiet screen or an absence of a nearby alert is not a property-specific safety certificate. Public Infobanjir and DID flood alerts.

Ask the relevant authorities and a suitably qualified adviser what flood information is available for the precise site. Record the map date, coverage and limitations. Do not turn a regional map colour into an unsupported prediction of water depth at your loading door.

Keep current monitoring, historical evidence and forward-looking professional assessment in separate sections of your decision record. They answer different questions.

References: Public InfobanjirDID flood alerts

Request a specific history, not a general assurance

Ask the owner or manager for written details of known water ingress, external flooding and access-road closures. Request dates, affected areas, photographs, repair records and relevant drainage works where available. Clarify whether “no flooding” means no water inside the building or no disruption anywhere around it.

With permission, speak to neighbouring occupiers about their experience. Their recollections can identify questions to investigate, but are not independently verified engineering evidence. Distinguish what someone witnessed from what they heard.

Look for explanations behind recent floor repairs, repainted lower walls or replaced electrical equipment. These are prompts for questions, not proof of flooding. Avoid accusing an owner of concealment based on appearance alone.

Inspect drainage as a connected system

During the viewing, note the positions of drains, gutters, downpipes, loading ramps and low points. Ask where surface water is intended to go and who maintains each part of the system. Obtain available drainage plans and maintenance records.

Check whether shared drains, estate roads or neighbouring works influence the premises. Ask about recurring blockages and how maintenance requests are handled. A clean drain inside the boundary does not answer what happens farther downstream.

Have a qualified engineer assess levels, discharge routes and any proposed protective works. Do not rely on a visual inspection to judge drainage capacity or design a flood barrier. Never enter a drain or approach moving floodwater to collect evidence.

Examine access and recovery, not just the floor

Consider whether staff, emergency services and delivery vehicles could reach the site if the usual approach were disrupted. Identify alternative routes and verify that they are suitable for the vehicles concerned.

Ask your operations team which equipment, stock and records would be hardest to replace. Review safe shutdown arrangements and the practical location of vulnerable equipment with the appropriate specialists. Estimate recovery requirements using your business’s own information rather than generic downtime assumptions.

These questions may reveal that a building remaining dry would still leave the business unable to operate.

Resolve insurance and responsibilities before commitment

Give your insurer or broker accurate property and operational information. Ask which flood-related losses are covered, what exclusions or excesses apply, and whether business interruption cover responds to the scenarios that concern you. Obtain written terms rather than assuming cover exists.

For a lease, clarify responsibility for drain maintenance, structural repairs and agreed mitigation works. Have your solicitor review the allocation of obligations and any conditions you need before occupation.

Close the assessment with a list of confirmed facts, missing evidence and professional recommendations. If a material question remains unanswered, reflect that uncertainty in the decision instead of labelling the property safe. This is due-diligence guidance, not flood, insurance or legal certification.