A concrete warehouse handles half a metre of floodwater fine. The building is still standing the next morning. The stock is not.

That is the whole difference between screening a house and screening a warehouse. For a house, the question is whether the structure and the people are safe. For a warehouse, the structure is rarely the issue and the contents are almost always the issue.

Work out the cost per centimetre first

Before you look at any map, work out what water actually costs you.

• What is the average value of stock on the floor?
• How much of it sits below one metre?
• What is on pallets, and how high is a pallet?
• Which items are total losses when wet, and which are salvageable?
• What does a full stock write-off cost, including the sales you cannot fulfil while you rebuild?

Now you have a number to weigh a site against, and the hazard screening turns from an abstract rating into a budget line.

What to screen at a candidate site

1. Mapped flood susceptibility at the exact coordinates of the building, not the industrial estate entrance.
2. Elevation, and specifically the finished floor level relative to the road and the yard.
3. Distance to the nearest mapped waterway. Industrial land is often cheap because it is on low ground near a channel.
4. Storm surge exposure if the site is anywhere near a coast, which many port-adjacent warehouses are.
5. Slope and landslide susceptibility if there is high ground behind the site.
6. Distance to the nearest mapped active fault, which is a structural design input, especially for racking. High racking in an earthquake is a serious hazard to people.

The general site-selection version is in picking a site for a shop, warehouse, or clinic.

The things that decide the outcome, beyond the map

Loading dock level. A dock designed for truck bed height is often the lowest opening in the building. That is where water enters.

Yard drainage and where it discharges. A big paved yard produces a lot of runoff. If its outlet is a channel that backs up, the yard becomes the retention pond.

Racking base and the bottom pallet. The cheapest flood mitigation in a warehouse is a rule that nothing valuable sits on the floor. Raising the bottom beam changes the loss curve immediately.

Power and control gear. Panels, UPS, chargers, compressors. If they are at floor level, the recovery time after a flood is measured in weeks rather than days.

Access for trucks. The building can be dry while the approach road is impassable. For a distribution operation that is the same outcome as flooding.

Insurance and the business case

Insurers price stock cover on location and on what you do about it. A site in a mapped high susceptibility zone with everything on the floor is a different proposal from the same site with raised racking, elevated panels, and a documented flood plan.

Bring the screening to the conversation. It also belongs in your lease negotiation, because a landlord who knows the site floods should be sharing that risk. See how a hazard profile affects insurance cost.

Checklist for a warehouse site

1. Screen the exact coordinates of the building footprint.
2. Compare finished floor level to the yard, the road, and the loading dock.
3. Identify where yard drainage discharges and whether that channel backs up.
4. Calculate stock value below one metre and treat it as the exposure.
5. Raise the bottom rack beam and move power gear above the expected line.
6. Check truck access separately from the building.
7. Write a flood plan with a trigger, an owner, and a two-hour version.

The two-hour plan

Most warehouse flood losses are avoidable in the last two hours if somebody has authority to act. The plan needs three things: what tells you to start, who decides, and what gets moved first.

Write it down. Put a copy at the gate. Rehearse it once. This is the cheapest risk reduction in the whole operation, and it is worth more than any single piece of infrastructure.

The honest limit

A hazard screening reports mapped susceptibility, elevation, slope, and distances at a point from public national datasets. It does not survey a building, assess racking, or model the drainage of a specific industrial estate. Those need a licensed structural and civil engineer and a proper site survey.

CheckHazard does not replace a professional geotechnical or engineering survey.