When people screen a house for hazards, they are mostly thinking about safety and repair cost. When the building is a shop, a warehouse, a clinic, or a small factory, a third number shows up and usually dominates: how many days you cannot operate. This post is about screening a site with that number in mind.

Downtime is usually the expensive part

Damage is a one-time bill. Downtime repeats every event and it compounds. A day of ankle-deep water on the shop floor might cost very little in repairs and still cost a week of trading, spoiled stock, staff you paid anyway, and customers who found somewhere else to go.

That changes what "acceptable risk" means. A homeowner might reasonably accept a lot that floods shallowly once every few years. A business that cannot trade for four days when that happens is looking at the same hazard with a very different multiplier.

So read the flood finding with frequency in front. Our report shows the modelled scenarios separately, 5, 25, and 100 year, so a site that is exposed in the ordinary case is visibly different from one exposed only in the rare case. If the return period idea is new, flood return periods explained covers it.

The ground floor is the business

Almost every value in a commercial building sits at the level water reaches first. Stock, chillers, servers, the electrical panel, the generator, the delivery bay, and the customer entrance are all typically on the ground floor or below it.

Three findings deserve close reading for that reason:

• Elevation. Under 2 metres above sea level is treated as high exposure and 2 to 10 metres as moderate. On flat coastal or reclaimed land, a metre of difference between two candidate sites is a real operational difference.
• Waterway distance. Inside 20 metres of a mapped channel is very high, inside 50 metres high, and inside 150 metres worth noting. Warehouses often sit near creeks and esteros because that land was cheap, and it was cheap for a reason.
• Flood level, including the edge cases. A site outside a polygon by less than 50 metres is reported at the neighbouring level, because a mapped boundary is a model rather than a fence. For a business, treat "just outside" as inside and plan accordingly. The layer detail is in the flood susceptibility brief.

If the site is a lease rather than a purchase, none of this stops being your problem. The landlord owns the building. You own the interruption.

Access decides whether you can trade at all

Your site can be dry and still be unreachable. If the approach road floods, deliveries do not arrive, staff cannot get in, and customers do not come. That is why our report includes a neighbourhood section that lists what sits within 2 kilometres of the address, including major roads, schools, and health facilities.

Read it as an operations map, not as trivia:

• Major roads. How many independent ways in are there, and do they cross the same low point or the same bridge?
• Health facilities. Relevant if you have staff on machinery, and a proxy for how quickly the area gets attention after an event.
• Schools. They are the usual evacuation centres, which tells you where the surrounding population goes and which roads fill up.

Then add the questions no dataset answers. Where do your staff commute from, and what happens to those routes in a storm? Where does your stock come from? If your supplier and your site flood in the same event, you have one risk, not two.

What your insurer, your lender, and your landlord will ask

Commercial cover is priced on exposure, and someone will eventually ask what you knew. Flood and catastrophe cover for business property is not automatic, and the terms shift with location. A screening report in your file at the point of the decision is cheap evidence that the site was assessed rather than assumed. The residential version of this conversation is in how a hazard profile affects insurance cost.

If you are the one developing the site rather than occupying it, the questions widen further, and hazard screening for subdivisions and housing projects covers that end.

A site-selection checklist

1. Screen every candidate site at its exact coordinates before you shortlist, not after you negotiate.
2. Compare sites on the same findings, side by side: flood level and return period, elevation, waterway distance, storm surge, slope, fault distance.
3. Walk the approach roads, and identify the lowest point on each route in.
4. Ask the neighbouring businesses how many days they lost in the last two big storms. They will tell you, and they have no reason to sell you the location.
5. Price the interruption, not only the repair. Days closed times daily margin is the number that should drive the decision.
6. Plan the ground floor around the answer. Raise the electrical panel, put stock on racking rather than the slab, and know where the generator sits.
7. Put the screening report in the lease or purchase file, and revisit it if you renew.

The honest limits

Hazard screening describes terrain and modelled hazard at a regional scale. It does not know about the pumping station two streets away, the drainage the industrial park upgraded last year, or how the building itself was constructed. It also cannot price your specific interruption, because only you know your daily margin and how fast your supply chain recovers.

What it does is give you a consistent, comparable read on every site you are considering, in minutes, before you commit to a lease term or a purchase price. For a decision that will hold your business for the next five or ten years, that is a very small amount of work for the amount of money involved.

CheckHazard does not replace a professional geotechnical or engineering survey.