How to Read a Flood Risk Report: Understanding Your Score

Every report leads with a single 0–100 score (lower is safer) and a Low/Moderate/High label — but the number alone isn't the point. Underneath it, every report breaks the score down factor by factor specifically so you can see why an address is rated the way it is, not just trust a black box.

Each of the three factors — ground elevation, recorded flood history, and distance to the nearest canal/river — gets its own score, weight, and plain-language explanation. A high overall score driven mostly by low elevation tells a different story than one driven mostly by recent flood history, even at the same number.

When a factor's underlying data couldn't be retrieved for an address — most often flood history, which depends on a GISTDA API we're still validating full access to — we say so explicitly rather than guessing. The score is then calculated from the remaining available factors, with their weights redistributed, and never padded with an assumed value.

Every report also lists factors that aren't part of the score at all yet — currently, local drainage and pumping capacity, because no validated public data source exists for it. Seeing what's excluded matters as much as seeing what's included; see our Methodology page for the full breakdown of weights and sources.

A report is meant to focus your due diligence, not replace it — a Low score is a reasonable green light to proceed with normal checks, while a Moderate or High score is a signal to ask the building or seller more specific questions (drainage, past flood incidents, insurance history) before committing.