Every serious property decision in Ghana turns on three questions that a listing photograph cannot answer: will this flood, does the seller actually own it, and is the price real? A risk score exists to compress those three into something you can compare across properties. It fails the moment it becomes a single opaque number, so the only useful way to read one is to decompose it.
The three factors
Asta scores each factor independently from 1 to 10, where 1 is lowest risk. They are deliberately not blended into a weighted average, for a reason covered further down.
1. Flood and drainage exposure
Derived from elevation, distance to the nearest drain or watercourse, upstream catchment area, and recorded inundation during the June and October rains. Exposure follows topography, not prestige: a new build on a local depression in an expensive suburb can score worse than an older property on the Legon ridge.
- Low-lying parcels on the Odaw catchment carry structurally higher exposure.
- Properties immediately downstream of a blocked or undersized storm drain inherit that drain's failure history.
- Recent construction upstream changes runoff, so the score is refreshed each rainy season rather than set once.
2. No-build & demolition risk
Whether the parcel sits in a zone where building is restricted or structures can be demolished: statutory watercourse setbacks, storm-drain buffers, wetlands and other protected areas. These are the plots cleared in a demolition sweep, and the exposure is invisible from a photograph.
Asta reads this from public data — watercourse and drainage geometry, statutory setback rules and Ghana’s protected-area registry — and flags the zone on the map. It does not assess land title: for the seller’s legal right to sell, commission a formal Lands Commission search on the specific parcel.
3. Price deviation
Asking price measured against comparable asking prices in the same locality and build-quality band, adjusted for cedi depreciation and material cost inflation. Asking-price averages — the figure most portals publish — are circular, because they measure what sellers hope for rather than what buyers paid.
A composite risk score is not an average. One severe no-build flag caps the entire score, because a 12% yield is worth nothing if the building comes down.
Reading the composite
The composite takes the worst material factor rather than the mean of the three. A property scoring 1.2 on flood, 1.4 on price and 7.9 on no-build is a 7.9, not a 3.5. Averaging would let two comfortable factors dilute the one that can lose the entire principal.
| Composite | Reading | What it usually means | Action |
|---|---|---|---|
| 1.0 – 2.9 | Low | No setback conflict, no flood history, price within ~10% of comparables | Proceed with standard checks |
| 3.0 – 5.9 | Moderate | One unresolved factor, most often price | Negotiate against the specific factor |
| 6.0 – 7.9 | Elevated | Material flood exposure or a no-build setback conflict | Legal review before any deposit |
| 8.0 – 10 | Severe | Inside a demolition buffer, or repeated inundation | Stop — this is not a discount |
Three ways people misread the number
Treating a high score as a bargaining chip. Price risk is negotiable; a demolition order is not. A discount does not move the setback line.
Assuming a new build is a low flood score. Construction quality does not change the catchment a property sits in.
Trusting a score with no visible inputs. If a platform won't show you what fed the number, the number is marketing. Every Asta factor lists its inputs and refresh cadence on the property's Dossier.
Checking a property yourself
None of this requires our platform. If you're doing it manually: commission a Lands Commission search on the specific parcel, visit during heavy rain rather than dry season, obtain at least three transacted comparables rather than asking prices, and physically inspect for occupation. Asta exists because that sequence takes weeks and is close to impossible from abroad — not because the sequence is secret.