Flooding and land in Bosham
Figures last changed 20 October 2026. House prices for Bosham are on the main Bosham page.
On this page: Does Bosham flood? · Will Bosham flood more in future? · How often does Bosham get flood warnings? · Is the coast at Bosham eroding? · Are there old landfill sites near Bosham?
Does Bosham flood?
From rivers and the sea, parts of it can. Ten of Bosham's 122 postcodes have their centre point inside Environment Agency flood zone 3, the highest band, and four more sit in zone 2. These zones cover rivers and the sea only and ignore flood defences. Rain is a separate risk: on the Environment Agency's surface-water map (read 18 October 2026), 39 of the 122 postcodes (32%) have high or medium risk within 25 metres of their centre point. Groundwater isn't mapped in either, and a postcode is not a house: check an exact address on GOV.UK.
Source: Environment Agency Flood Map for Planning · Check an address for flood risk · What the flood zones leave out · New builds and Flood Re.
What locals say
- Highgrove, the 300-home Barratt and David Wilson estate at Broadbridge, is the live argument, and the record backs residents' worries. At the 2022 planning committee the developer's drainage engineer agreed that parts of the site suffer groundwater flooding, which is why it needs lined drainage basins and underground storage; the Environment Agency's river and sea flood zones do not show groundwater. Chichester planning committee, 9 November 2022 (BO/21/00571/FUL)
- Water has always gathered here: Brooks Lane takes its name from the brook, and Bosham Stream and its ditches run just to the west. Before Highgrove was built, the field was known for standing water after long rain, draining into Brooks Lane and the A259; the Bosham Association recorded the lane being impassable for hours. Bosham Association objection to Highgrove
Will Bosham flood more in future?
Yes, noticeably more, on the Environment Agency's climate change scenario. Its long-term flood maps, unlike the flood zones above, count flood defences. From rivers and the sea, 14 of Bosham's 122 postcodes have their centre point at high or medium risk today, and 20 under the scenario, which runs to the 2050s with sea level rise to 2065; at high risk alone, twelve today and 19 then. From heavy rain, 39 have high or medium risk within 25 metres today, and 52 under the scenario. High risk means at least a 1 in 30 chance of flooding in any year, and medium means between 1 in 100 and 1 in 30. The maps were read on 18 October 2026.
Source: Environment Agency long-term flood risk maps, today and with climate change.
How often does Bosham get flood warnings?
The Environment Agency issued a flood warning for part of Bosham on eleven days in the ten years to June 2026, most recently on 30 March 2025. 31 of its 122 postcodes sit inside two Agency flood warning areas: "Bosham and West Itchenor" (Chichester Harbour), with warnings on eleven days; and "Bosham on the Bosham Stream", with none. No severe flood warning, the level that means danger to life, was issued in that time. Flood alerts, the earlier message that flooding is possible, went out on 45 days in that time, most recently on 18 February 2026. Warnings cover flooding from rivers and the sea, and groundwater in a few places, not heavy rain on its own. Each count is of days on which a new warning or alert went out, so updates on an event already running are not counted again.
Source: Environment Agency Historic Flood Warnings · Environment Agency flood warning and alert areas (real-time flood-monitoring API) · Sign up for free flood warnings.
Is the coast at Bosham eroding?
Not where homes are, on current plans. The shoreline plan for the 16.8 km of coast within 500 metres of Bosham's postcodes is to hold the line, keeping the existing defences, through to 2105. None of its postcodes has its centre point in land the Environment Agency's erosion map expects to be lost by 2105, if that plan is carried out and with its higher central allowance for climate change.
Source: Environment Agency National Coastal Erosion Risk Map 2024.
Are there old landfill sites near Bosham?
Yes. The Environment Agency's record of historic landfill sites shows three within 500 metres of a Bosham postcode, though none of its 122 postcodes has its centre point within 250 metres of one. The nearest is Brinkman Farms, which took inert waste such as soil and rubble between 1960 and 1990. The others are Clay Lane and Cut Mill. A historic landfill is an old tip with no environmental permit in force: one that closed before tips were licensed, or whose licence has since ended. The Agency says much of its record comes from a national survey in the early 1990s, so it may be incomplete, and some boundaries are only approximate. An old tip nearby does not by itself mean a problem; the council's contaminated land register, or a search on an exact address, says more.
Figures cover 122 postcodes in Bosham. How these figures are made.