Flood Risk Assessment in Yeovil

A flood risk assessment in Yeovil, Somerset, has to deal with two kinds of water. The River Yeo runs along the eastern edge of the town past Pen Mill and Newton Surmaville, while inside the town the trouble comes mostly from rainfall that the drains and small streams cannot take, with the Dodham Brook cutting through Preston Plucknett and West Hendford towards the centre. Clients come to our consultants for flood risk assessments in Yeovil when they apply for planning permission, buy a property, arrange a mortgage or renew insurance, and for sequential and exception tests and surface water drainage strategies.

Here Yeovil means the built-up town as the Office for National Statistics maps it: the centre, Hendford and Pen Mill, Westfield, Preston Plucknett, Alvington and Houndstone to the west, Lufton on the western edge and Brimsmore to the north, covering the BA20 and BA21 postcode districts. Part of Brimsmore lies in Yeovil Without parish. Somerset Council decides planning applications in the town and is also the lead local flood authority.

South Somerset's own Local Plan singles out Yeovil among the district's towns where surface water flooding is an issue, and the Environment Agency's catchment plan for the Parrett warns that the town's main problems in future may come from intense summer storms overwhelming its sewers and smaller streams.

Send a Yeovil address to enquiries@unda.co.uk or call 01293 214444. Before we quote, we look at where the site sits against the Yeo floodplain, the Dodham Brook and the surface water hotspots the Somerset Rivers Authority has mapped.

Where water gathers in Yeovil: the Somerset Rivers Authority's hotspots

The town centre, two trading estates and several housing estates. Somerset County Council ran the study for the Somerset Rivers Authority, with Yeovil Rivers Community Trust as contractor. The trust surveyed parts of the town on the ground to check whether places shown at risk on the Environment Agency's surface water maps really do flood from rain and sewers, then cross-checked the results against the 2019 strategic flood risk assessment. Its Yeovil urban SuDS study ranked these as the highest priorities:

• Town centre. The Quedam, the Cattle Market, Glovers Walk, Yeo Leisure Park, the Old Station Road area and Tanyard View.
• Hendford side. Horsey Lane, Millbrook, the former police station site and West Hendford.
• Pen Mill. The Pen Mill Trading Estate, Fiveways School, Pen Mill station and Camborne Grove and Camborne Street.
• Milford. The Milford valley and Elizabeth Flats, where the open ground is large enough for bigger storage features.
• Westfield and the Lynx Trading Estate. The Westfield estate and Westfield Academy, and the industrial units on the Lynx estate.

The study was meant to feed a surface water management plan for the whole town, which the authority said it was funding so that stronger bids could be made for national flood grant. In its 2025-26 report Yeovil is again one of 15 places where local flood risk measures were under consideration. For a developer the hotspot list matters more than the flood zones: a site at Glovers Walk or on the Lynx estate can be in Flood Zone 1 and still sit where the authority's surveyors found water standing in the road.

Is Yeovil in a flood zone? The Yeo on one edge and a brook through the middle

Very little of it. Unda's own overlay of the Environment Agency's Flood Map for Planning on the ONS outline puts about 3% of the built-up area in Flood Zone 2 or 3 and a little over 1% in Flood Zone 3. Those strips follow two watercourses, and the Local Plan records that development south-east of the town has been held back by the Yeo floodplain as well as by steep ground.

The Environment Agency's warning area for the River Yeo from Sherborne to Yeovil runs down to the Old Mill Farm area and names Yeovil Junction station, Newton Surmaville, Chudleigh Mill and the Yeobridge Trade Park. Below that, separate warnings cover the river from Yeovil to Limington and at Mudford. The river is gauged at Pen Mill, where the normal range is 0.12 m to 3.10 m and property flooding becomes possible above 4.09 m. The highest level on record there is 4.57 m, on 28 December 1979. Pen Mill readings appear on our live river levels map alongside the other Somerset gauges.

Check a BA20 or BA21 postcode

Enter a Yeovil postcode in the map below to see the planning flood zones, the surface water extents and any warning in force at that point. For an address outside Yeovil, our flood risk map covers the rest of England. The coral line shows the ONS built-up area, and the Yeo floodplain mostly sits just beyond it to the east.

Somerset Council's local plan evidence page lists the 2019 Level 1 strategic flood risk assessment for South Somerset and Somerset West and Taunton, with a separate set of Yeovil maps. A new Level 1 assessment covering the whole of Somerset now sits in the evidence for the next local plan; the Level 2 study that will test individual sites has not yet been published.

From the 1979 Yeo peak to the wet winter of 2026: Yeovil's record

Yeovil has no large recorded river flood of its own in the Environment Agency's outlines. The river record sits downstream at Mudford and Ilchester, and what the town has instead is a short list of small, dated events:

1. 28 December 1979. The Yeo at Pen Mill reached 4.57 m, still the highest level on the gauge and almost half a metre above the point where property flooding becomes possible. Upstream, the Agency's outlines show the river overtopping through Sherborne that December.
2. 25 November 2012. An outline recorded as groundwater or a high water table, at Compton Road by Babylon Hill on the Dorset side of the town's eastern edge, in the same week as the November 2012 river floods downstream on the Yeo and Parrett.
3. 24 December 2013. The Yeo spilled out of its channel beside Sherborne Road near the golf course, in a small outline the Agency filed under the winter of 2013 to 2014.
4. February 2026. During the Somerset major incident, the council's 11 February update listed the A30 at Hendford Hill as closed by fallen trees and bank slippage, and Bridgehampton Road near Yeovil among other road closures. The update gives no Yeovil property count.

The short list does not mean low risk. The Agency's outlines record few surface water floods anywhere, and the town's hotspots come from the authority's ground surveys, not from the river record. A Yeovil assessment therefore leans on the surface water maps and the 2019 strategic assessment more than on the history of the Yeo.

Two catchments on one town: why west Yeovil drains towards Martock

Yeovil sits across a divide. The centre, Pen Mill and the eastern estates drain to the Yeo, while rain falling on the newer estates to the west and north-west runs into Wellhams Brook and on to the Parrett near Martock. In 2017 the Somerset Rivers Authority paid to desilt a pond at Lufton College, restoring 3,000 m³ of flood storage, and fitted a penstock so that Martock's flood wardens can hold water back in heavy rain. The authority described the site as downstream of major development on Yeovil's west side, so runoff from new building around Lufton and Brympton adds to the flows Martock's wardens are managing.

The ground helps in places. The Local Plan cites the strategic assessment as finding a relatively high potential for SuDS across South Somerset because of its permeable geology, so a soakaway is the first option to test. Our soakaway and ground conditions guide explains the infiltration testing that settles it, and where the ground will not take the water, the discharge has to go to a watercourse or a sewer at a controlled rate.

The policies a flood risk assessment in Yeovil is judged against

Somerset Council still decides Yeovil applications under the South Somerset Local Plan 2006-2028, adopted in March 2015, until the new Somerset plan replaces it. The policies and standards below are the ones a Yeovil report is read against.

The plan itself is on the former South Somerset council's document site, and the county standards are published as the Somerset local SuDS design standards. Our guide to the 2025 National Standards for SuDS sets out how the national rules sit underneath the Somerset ones, and the article on the sequential test after Mead covers how areas of search are now argued.

Keyford, the north-east extension and the next Somerset plan

The 2015 plan provides for at least 7,441 homes at Yeovil, about 5,876 of them inside the existing town and 1,565 in two urban extensions. Three named sites, and the plan that will replace them, matter for flood work:

• Keyford, the south urban extension. About 800 homes under Policy YV2 on land in East Coker parish, just south of the built-up town and outside the coral outline.
• The north-east urban extension. About 765 homes under the same policy on the north-east side of the town, towards Mudford and the Yeo valley.
• Summerhouse Village. Housing-led regeneration of council car park land at Stars Lane beside the Dodham Brook, where the plan flags flooding mitigation as a cost the scheme has to carry.
• A plan for the whole county. Somerset Council's Local Plan timetable shows a draft plan consultation from 10 September to 29 October 2027 and adoption expected on 16 March 2029; until then the 2015 plan and its Yeovil policies stand.

Reports we prepare for Yeovil sites, from Pen Mill to Lufton

The work in Yeovil follows its water: the Yeo on the east side, the Dodham Brook through the west and centre, and surface water nearly everywhere else.

• Applications to Somerset Council. New homes or commercial floorspace in Flood Zone 2 or 3 by the Yeo or the Dodham Brook, any site of a hectare or more, or land in a mapped surface water hotspot needs a flood risk assessment for planning that answers Policy EQ1.
• Rain, brook and river at one address. In Yeovil a flood risk assessment weighs surface water and the sewers first, because the town's recorded problems come from them, then the brook and the Yeo where a site is near either.
• Buying near Pen Mill or Glovers Walk. A home or unit in the Yeo warning area or on a surveyed hotspot street needs more than a search result, and a flood risk survey for property purchase looks at that building, its floor level and its drainage before exchange.
• Infill on the brook corridor. Housing on a windfall plot in Flood Zone 2 or 3 along the Dodham Brook has to show, through the sequential and exception test, why no lower-risk site across South Somerset would do.
• Runoff the council can accept. Somerset Council expects a drainage strategy that holds peak flows to greenfield rates for three storm sizes, with no 5 l/s floor to fall back on.
• West of the watershed. On the estates around Lufton and Brympton, where water heads for Wellhams Brook and Martock, a surface water drainage strategy shows the soakaway tests or the controlled discharge that keeps runoff from rising downstream.
• Conditions on the urban extensions. Where a permission at Keyford or on the north-east extension comes with a drainage condition, our discharge of drainage conditions work supplies the calculations and details the council's flood team asks for, phase by phase.
• Yeobridge Trade Park and the warning area. Businesses and homes inside the River Yeo from Sherborne to Yeovil warning area can tie their response to those warnings with a flood warning and evacuation plan.
• Trading estates on the hotspot list. The Pen Mill and Lynx trading estates are both on the authority's priority list, and a business continuity assessment sets out how a firm keeps working when the drains back up.
• Aerospace and employment land. The Local Plan wants about 5.16 hectares of employment land in Yeovil's two urban extensions and new aerospace and high-tech firms in the town; where those buildings target a BREEAM rating, a BREEAM flood risk assessment covers the flood risk credit.
• Zones drawn from local evidence. Where the Dodham Brook's zones come from local evidence or a coarse model, flood modelling gives a site its own flood levels to set floors and layouts against.

Sherborne upstream, the Parrett downstream, and the villages around Yeovil

Yeovil sits within our Somerset area page, and the council's drainage requirements across the county are set out on our page for Somerset Council. The Yeo arrives from Sherborne, just over the Dorset border, and joins the Parrett south of Langport; our River Parrett page follows that water to the Levels and to Bridgwater. Sites around the county town have their own page for Taunton, and those over the border to the south fall under Dorset Council, with Dorchester as its county town.

Yeovil Marsh, Mudford, Brympton d'Evercy, West Coker, East Coker, Barwick and Bradford Abbas all lie outside the coral outline, as does Yeovil Junction station. Mudford has its own Yeo warning area. A few properties at Babylon Hill fall inside the outline but over the boundary in Dorset, where Dorset Council is the planning authority. Our areas we cover page lists every place with a page of its own.

Who answers when Yeovil floods

Responsibility depends on where the water comes from, so the first call goes to the body that owns that source.

For practical advice on preparing a home or business, the county's Somerset Prepared flooding page collects the numbers above in one place.

Questions buyers and applicants ask about flooding in Yeovil

To talk through a site in Yeovil, call one of our experienced flood risk consultants on 01293 214444 or email enquiries@unda.co.uk. Every Yeovil report is checked and signed off by a senior consultant; our consultants are chartered, and Unda Consulting Limited is a CIWEM Business Partner.