Parts of Maidstone are at risk of flooding, and most of it isn't. Only a small share of postcodes sit in the river flood zones. More are exposed once rainwater running off the streets is counted. A few hundred homes are at high risk from the rivers. The risk is concentrated, so the address matters far more than the town's name.
The River Medway runs through the middle of town, with the Len and the Loose Stream joining it, so river flooding comes with the geography. On the Environment Agency's mapping, about 2% of the area's postcodes fall in flood zone 3, the high-probability zone, and about another 2% fall in flood zone 2, the medium-probability fringe beyond it. The two zones don't overlap. The agency has 144 recorded flood events for the area, and the latest was in December 2013, when the main river overtopped a channel that had no raised defences.
Surface water, which is rain the drains can't keep up with, is a separate risk and doesn't follow the river. It turns up in the postcode figures further down, which count it alongside rivers and sea and put more of Maidstone at risk than the flood zones alone do.
Allowing for climate change, the Environment Agency's climate-adjusted flood zone takes in about 4% of postcodes. That's a modelled look forward, not a record of anything that has already happened, and it's the figure to check if you plan to stay for decades.
For insurance, a home in or near a flood zone can cost more to cover and may come with a higher excess or a flood exclusion. Get a quote for the specific address before you commit, not after exchange.
On a wider postcode measure, which counts surface water alongside rivers and the sea, about 10% of postcodes are at high risk on at least one measure, about 14% at medium risk on at least one and about 34% at low risk on at least one. Those bands overlap with the flood-zone figures above and measure something different, so the two sets shouldn't be added together.
Counting homes rather than postcodes, the Environment Agency's rivers-and-sea mapping lists 3,073 properties in the postcodes that carry any risk at all. Of those, 373 are at high risk, 267 of them homes, 278 at medium risk, 993 at low risk and 408 at very low risk. Postcodes with no river or sea risk don't appear in that count at all.
In the modelled high-probability flood extent, about 2% of postcodes have no defence in the model and about 1% have one. A defence being in the model means something stands between the river and those streets. It doesn't mean the homes behind it are safe, and defences can be overtopped or fail.
On the national coastline mapping, the closest postcode is about 240 metres from the coast, but the typical postcode is about 3.3 kilometres away, and fewer than 1% of postcodes sit within 500 metres. The 500-metre line is a threshold in the data, not a verdict on any particular house.
The shoreline management plan for this stretch sets a policy of holding the line for the next 20 years, then managed realignment over the 50-year and 100-year horizons. Holding the line is a stated intention to maintain the existing defences. Managed realignment means allowing the shoreline to move back in a controlled way. Neither is a guarantee, and neither is a defence that already exists.
At Dover, the nearest tide gauge, sea level rose by about 2.2 millimetres a year across its record from 1961 to 2010. That's a measured historical rate, not a forecast.
Maidstone's flood risk is middling: most of the town is clear, but there's a real risk near the Medway and on the streets where surface water collects. Check the specific address, and treat anything near the river as needing a closer look.