Where flood risk applies in Plymouth
The council's Local Flood Risk Management Strategy (September 2026) sets out four sources of flood risk, which can combine:
- Tidal floodingExtreme high tides, sometimes combined with surges and storms, cause most tidal flooding. The areas with the most properties at risk are the Barbican (Sutton Harbour), Marsh Mills and Stonehouse, with others including Millbay, Hooe, Oreston, Turnchapel, Embankment Road and Laira, West Hoe and Royal William Yard.
- Wave overtoppingThe Environment Agency's Plymouth Coastal Modelling Study (2018) found that waves overtopping the sea defences add to flooding where water is trapped behind them, so some sites next to the foreshore are at greater risk than the flood zones alone suggest.
- Rivers and streamsWatercourses through the city can overtop after heavy rain where channels or culvert screens are restricted or blocked, and development in their floodplains puts property at risk.
- Surface water and tide-lockingMost of the urban area is an Environment Agency Critical Drainage Area, where drainage is at or near capacity and higher surface water standards apply. High tides can also stop surface water outfalls discharging, which the strategy calls tide-locking.
What Plymouth City Council will look for
Plymouth City Council applies the national tests in NPPF Chapter 18 and the Planning Practice Guidance, supported by its Strategic Flood Risk Assessment. A Sequential Test submitted with a Plymouth application should normally:
- Confirm the flood zone and vulnerabilityUse the current Environment Agency Flood Map for Planning and the NPPF Annex F vulnerability class for the proposed use.
- Justify the area of searchNational policy says the area of search should reflect the catchment for the type of development and the need it serves. For most housing in Plymouth that is the city as a whole; for a smaller scheme serving a particular neighbourhood, a narrower area may be more defensible.
- Assess the council's own sources of sitesPlymouth City Council's housing trajectory (2025/26), the Plymouth and South West Devon Joint Local Plan allocations in Plymouth and the Brownfield Land Register are the obvious places to start, and omitting them is a common reason for challenge.
- Evidence every discounted siteWhere an alternative is ruled out as unsuitable, too small or not available in a similar timeframe, give the reason and the evidence. Ownership alone is not enough.
- Screen for the Exception TestState whether the Exception Test applies under Annex F Table 3, and if it does, provide it, drawing on the site-specific flood risk assessment.
Plymouth-specific pitfalls
- Relying on defencesPlymouth's tidal defences include the Sutton Harbour lock gates and the Plymouth Sound and Mount Batten breakwaters. They matter for the site-specific flood risk assessment, but the Sequential Test uses flood zones as if the defences were not there.
- Climate changeSea level rise and stronger storms are expected to increase tidal flood risk around the city, so a site's future flood risk over the lifetime of the development matters as well as today's flood zone.
- Land supply evidencePlymouth publishes its housing supply sites and allocations, not the sites it has assessed and discounted. Our reports use the published supply, allocations and brownfield register, and you may want to add other alternatives you know of.
- Housing-led evidence for non-housing usesThe housing trajectory covers homes only. For employment, retail or community uses, you may need to add alternative sites from other sources.
Fixed-fee Sequential Tests for Plymouth
We have built our Plymouth Sequential Test on published Environment Agency and Plymouth City Council data. Plot your site on our Plymouth Sequential Test page and we'll deliver a submission-ready report within 24 hours of payment for £300. Exception Tests are £450 within 48 hours.
New to the subject? Start with our general guide: what is a flood risk Sequential Test? We also cover other council areas at the same fixed fee. For wider planning help, see planning consultants in Plymouth.
Source: Plymouth Local Flood Risk Management Strategy, Part 1 (Plymouth City Council, September 2026).
Sequential Test guides for other council areas
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Frequently asked questions
Does Plymouth City Council require a Sequential Test?
Yes, for most development in Flood Zones 2 and 3, in line with national policy. Some minor development and most changes of use are exempt, and sites allocated in the local plan may not need the test repeated.
What area of search should I use in Plymouth?
National policy says the area of search should reflect the catchment for the type of development and the need it serves. For most housing in Plymouth that is the city as a whole; for a smaller scheme serving a particular neighbourhood, a narrower area may be more defensible. The reason must be explained in the report.
Do flood defences mean I don't need a Sequential Test?
No. Flood zones for the Sequential Test are assessed without defences. Defences are taken into account in the site-specific flood risk assessment and the Exception Test, not the Sequential Test.
How much does a Sequential Test cost in Plymouth?
Our fixed fee for a Plymouth flood risk Sequential Test or alternatives assessment is £300, delivered within 24 hours of payment. An Exception Test is £450, delivered within 48 hours.
This guide is general information for applications in England and is not advice on your specific project. Requirements differ in Wales, Scotland and Northern Ireland, and every council publishes its own local validation list, so always check the detail with your local planning authority.