Yes, and on a published schedule. The sea reaches the lower lane at spring tides. About one in ten of the parish sits in the highest river-and-sea zone. Over half sits in the climate-adjusted future zone. Anyone buying here is buying into all of that.
On river and sea flooding, the official picture sits in the Environment Agency's flood-zone designations. About one in ten of Bosham falls inside Flood Zone 3, the high-probability zone, and a further one in twenty inside Flood Zone 2, the medium-probability zone. The historic-flood share for the parish is recorded at zero, which means no part of Bosham appears on the register of properties that have actually flooded from a main river or the sea in the published data window. That is the formal record. The lived record, including spring tides bringing water up the lower lane, is a separate Bosham reality that has been documented in the village for centuries. The shortest distance from a Bosham postcode to the coast is five metres, and over half the postcodes sit within five hundred metres of the coast. This is a coastal village in the full geographic sense.
Surface-water flooding is the broader risk and the one that catches more buyers off-guard. About one in four Bosham postcodes carries a high surface-water flood risk. About one in nine sits at medium. About one in three sits at low. Surface-water risk is rain landing faster than the drains can carry it away, which on a low-lying peninsula with old infrastructure is a recurring fact rather than a freak event. The number that matters is the one in four at high risk, because that is the proportion of homes where any sustained heavy-rainfall event becomes a calculation rather than an inconvenience.
The forward look is where the figures move. Over half the parish, roughly fifty-six per cent of it, sits in the Environment Agency's climate-adjusted flood zone, which is the area projected to be at risk under modelled sea-level rise. The nearest tide gauge, at Portsmouth, has been recording for over sixty years and records sea level rising at roughly two millimetres a year. The shoreline-management policy for most of the parish is Hold The Line, which means the public-realm response is engineered defence rather than retreat. That is a planning decision that has been made. It is not a guarantee against any individual property flooding.
For insurance, any home sitting inside a Flood Zone 3 designation, or in a postcode flagged for high surface-water risk, should expect higher buildings-insurance premiums and a more involved underwriting process than a comparable home on higher ground further inland. Older properties may qualify for the industry's Flood Re scheme, which subsidises cover on flood risk for properties built before 2009. Homes built since 2009 are excluded from Flood Re, which matters in a parish that has added new-build stock into its mix. A flood-risk survey before exchange is the routine baseline for any Bosham purchase and informs both lender and insurer decisions.
Bosham's flood risk is real, geographically concentrated, and forecast to grow as sea levels rise on this stretch of coast. The village is below average for flood safety because the village is below average for flood exposure. That is the trade for a quay-side postcode and a Chichester Harbour view.