Most of Sawbridgeworth is not at serious flood risk, but the strip along the River Stort is. Very little of the town falls in the highest-risk river zone. About one postcode in nine rates high on at least one flood measure once rain runoff is counted alongside the river. Only a few dozen homes are at high risk from the river itself. The risk is real, and it is narrow.
The Environment Agency's river-and-sea flood zones put about 1% of the area's postcodes in Zone 3, the highest-probability band, and about 7% in Zone 2. Zone 2 is the medium-probability fringe outside Zone 3, so the two shares are separate bands and do not overlap. Both follow the eastern edge of town, where the Stort, the Stort Navigation and the railway run side by side towards Lower Sheering and Harlow Mill. The Stort has marked the county boundary for centuries, and on the flood maps it marks the edge of the risk as well.
Surface water, the rain that runs off roads and gardens faster than drains can take it, is mapped separately by the Environment Agency. It doesn't stay near the river, and that is why the postcode-level measure further down covers more of the town than the river zones do.
With the Environment Agency's climate allowance applied, the share of postcodes in the flood zones rises to about 12%. That is a modelled future in which the same river reaches further, and it is the version a buyer on a twenty-five-year mortgage will be living with.
Insurers price flood risk by individual property, and a house in a flood zone or with a recorded flood will usually cost more to insure. Some of those houses can only get cover on narrower terms. The flats at Lawrence Moorings stand on the old joinery works between the canal and the railway, and "Moorings" is a lovely word right up until an insurer reads the address. Put the exact address into the Environment Agency's long-term flood risk service and get an insurance quote while the purchase is still at the offer stage.
On the broader postcode measure, which counts a postcode if it rates at a given level on any one of several flood measures, surface water included, about 11% of postcodes rate high, 13% medium and 35% low. A postcode only has to fail one test to be counted, which is why these shares are larger than the river-zone figures above.
The Environment Agency's rivers-and-sea mapping lists only the 21 postcodes that carry some level of risk, and counts the properties inside them. Of 982 properties in those postcodes, 48 are at high risk, 22 at medium, 336 at low and 1 at very low, and 42 of the high-risk properties are homes. Counting homes makes the risk easier to picture. Forty-two front doors is a much smaller risk than "flood risk" in a search result makes it sound, unless one of those front doors is yours.
The Environment Agency's model also shows whether defences make a difference. About 2% of postcodes fall inside the high-probability flood extent when defences are left out, and only slightly fewer when they are put in. A defence counted in the model is not a promise that it will hold, and here the modelled defences barely move the number anyway. The agency holds nine recorded flood events for the area, the most recent in October 2001, when the main river overflowed its channel where there were no raised defences.
Flood risk in Sawbridgeworth is middling overall. It stays small across most of the town and gets serious along the Stort, so the house you choose matters much more than the town average.