Flood Risk Assessment in Tilbury

A flood risk assessment in Tilbury begins with the ground the town is built on: reclaimed Thames marsh, much of it lower than a high spring tide, and stays dry because of river walls, a set of lock gates at the docks and pumps that lift rainwater out to the estuary. We prepare flood risk assessments here for planning applications, house purchases, mortgages and insurance, together with sequential and exception tests and surface water drainage strategies, for sites from Tilbury Docks to the edge of Chadwell St Mary.

On this page Tilbury means the built-up area drawn by the Office for National Statistics: the old town around Civic Square and Dock Road, Tilbury Riverside and the cruise terminal, the docks and the Tilbury2 terminal on the former power station land, all in the RM18 postcode district. Chadwell St Mary to the north, West Tilbury and its marshes, and East Tilbury and Linford further down the river fall outside that outline but share the same council, the same Environment Agency warning area and much of the same evidence, so we cover them here too. Thurrock Council is a unitary authority: it decides planning applications and is also the lead local flood authority, so Essex County Council plays no part in drainage consultations here. The rest of the county is on our Essex page.

About seven-tenths of Tilbury's built-up area is in Flood Zone 3 and almost all of the rest in Flood Zone 2. The walls hold back the tide, so the test for any scheme here is what happens if they are overtopped or breached, which is how the council's own flood study treats the Thames.

Call 01293 214444 or email enquiries@unda.co.uk to talk through a Tilbury site with one of our flood risk consultants. Reports for sites in Tilbury come from Unda Consulting Limited, a CIWEM Business Partner.

Why does almost every site need a flood risk assessment in Tilbury?

Because the Flood Map for Planning puts nearly the whole town in Flood Zone 2 or 3, and in Thurrock a site-specific assessment is required for any development in either zone. The zones show the land as if the defences were not there. Tilbury's strategic flood risk assessment lists the town, with Grays and London Gateway, among the parts of the borough most exposed to the tide without its defences, and the marshes round it lie less than a metre above mean sea level.

• The zone split. Our own check of the Environment Agency's Flood Map for Planning against the ONS outline (26 October 2026) puts about 70 per cent of the built-up area in Flood Zone 3 and about 96 per cent in Zone 2 or 3. The small Zone 1 remainder is higher ground inside the town.
• The standard of protection. The Thames walls along the Thurrock frontage stand between 6.9 m and 7.2 m above Ordnance Datum and are recorded as protecting to a 1 in 1,000 year tide, according to the council's Level 1 Strategic Flood Risk Assessment (AECOM, July 2024).
• What is left. The same study treats the Thames threat as residual risk: water coming over the walls in an extreme tide, or through them where they fail. It modelled breaches at 21 points on the frontage for tides in 2125, and those breach maps, not the zone alone, set floor levels and refuge in a Tilbury assessment.
• More than the river. Rain falling on the town cannot drain by gravity at high tide, so surface water, sewer flooding and the storage area to the north each need their own answer in the same report (see the drainage section below).

That is why a house extension, a change of use to flats and a warehouse by the docks all come with the same question from the council. The answer differs in depth: a householder scheme needs a short, proportionate report, while a new block of homes needs breach levels, a place of safety above the extreme flood level and a drainage strategy as well. Our guide to residual flood risk explains how breach hazard is assessed.

Check a Tilbury, Chadwell St Mary or East Tilbury postcode

Enter a postcode in the map below for a first screen of flooding from the river and sea, surface water and reservoirs, using Environment Agency data; our flood risk map covers the rest of the country in the same way. The coral line is Tilbury's built-up area as ONS draws it, with the docks and Tilbury2 inside it. Chadwell St Mary, West Tilbury village and East Tilbury sit outside the line, and a postcode there still returns its own result.

River walls, lock gates and TE2100: how the tide is kept out of Tilbury

Tilbury is defended by a continuous line of walls and embankments along the Thames, by local defences inside the town and by tidal gates across the entrance to the docks. Most of the line was raised after 1953 under the Thames Barrier and Flood Protection Act 1972, and the works between Purfleet and Vange Creek were finished for the winter of 1982 to 1983. The Environment Agency maintains almost all of it.

The council's study says the barrier at the dock entrance, closed on high spring and surge tides, completes the defences for the port and over 5,000 properties in Tilbury, and the new gates take over that job. Tilbury sits in the Purfleet, Grays and Tilbury policy unit of the Thames Estuary 2100 plan, where the policy is P4: further action to keep pace with climate and land use change so that flood risk does not rise. The plan expects a riverside strategy by 2030, which does not yet exist, and defence owners to adapt and raise walls where needed by 2040, working with the council, developers and infrastructure providers. Draft Policy DMP29 adds that development near a defence must not stop it being maintained or raised. The Thames as a whole is covered on our River Thames page, and the Woolwich structure upstream on our Thames Barrier explainer.

One future option bears directly on Tilbury. TE2100 keeps open a new barrier further down the river at Long Reach, and the SFRA notes that water levels just downstream of such a barrier would be higher, so the tidal risk to Grays and Tilbury could rise. For now the extreme-tide mapping in the SFRA is used as a stand-in for that scenario.

Warnings come from the Environment Agency's East Anglia area. The Thames estuary from Shellhaven to Tilbury warning area covers the town, Mucking and Linford; the Coalhouse Fort and marshland area covers East Tilbury's riverside; and the Fobbing to Purfleet-on-Thames alert spans the whole frontage. The River Thames level at Tilbury gauge has a highest recorded reading of 5.05 m. Tide levels on that gauge and others can be followed on our live river levels map.

Pumps, sluices and the storage reservoir: why rain floods Tilbury

Most flooding Tilbury has seen since the 1950s has come from rain, not the river. The town is flat former marsh, the railway along its southern side acts as a barrier to flow, and the outfalls to the Thames close whenever the tide is high. When heavy rain meets a high tide, water backs up through ditches and sewers into roads and homes.

• Two drainage halves. The 2015 Local Flood Risk Management Strategy splits the town along a slight ridge. The eastern half is pumped to the river from World's End pumping station through the Chadwell Cross Sewer; the western half drains by gravity through Botney and Chadwell sluices via the East Dock Sewer.
• Main rivers in the streets. The East Dock Sewer and the Chadwell Cross Sewer are main rivers despite their names, so the Environment Agency has powers over them and landowners alongside carry riparian duties. Our guide to main rivers and ordinary watercourses sets out who maintains what.
• The storage area to the north. The Tilbury Flood Storage Area was built in 1972 to hold rainwater from the marshes and higher land before it reaches the town, and has been a raised reservoir under the Reservoirs Act since 1997. The Environment Agency's reservoir maps show Tilbury among the land that would flood if its embankment failed; our reservoir flooding explainer covers what that means for a site.
• Functional floodplain. Because it is built to store water, the storage area is Flood Zone 3b. Only water-compatible uses and essential infrastructure that passes the exception test can go there; homes, shops and industry cannot. Our Flood Zone 3b guide explains the rule.
• An area of critical drainage. Tilbury is one of the 14 Areas of Critical Drainage in Thurrock's strategy. Its tables count 366 homes in the drainage area at risk of surface water in a 1 in 30 year storm, 390 in a 1 in 100 year storm and 982 in a 1 in 1,000 year storm. A site in a critical drainage area needs a flood risk assessment even in Flood Zone 1.

The council's 2024 study modelled what new building around the storage area would do. Covering half or nine-tenths of the candidate sites with hard surfaces could deepen the water in the storage area by more than 0.1 m, eating into its capacity, and raising one site by 700 mm could push floodwater onto neighbouring homes. The study therefore asks the council to stop land raising there, keep the Zone 3b designation and hold every site in the catchment to its existing runoff rates and volumes.

Tilbury's flood record, from the 1953 surge to Quebec Road

The council's study names 1897, 1928, 1938 and 1953 as the largest tidal floods in South Essex and Thurrock. Since the defences were raised, the floods recorded in Tilbury have come from drains and sewers that could not empty into a high river.

1. 31 January to 1 February 1953. A lookout at Tilbury Fort saw the tide coming over the wall at about 11.20pm, and by 1am the water had reached the town. Some 2,500 houses and the fire station flooded, and about 6,000 people were left homeless, according to a Thurrock Local History Society talk; one death was reported in Thurrock. The strategy records depths of about 2 m to 3 m. The national picture is on our 1953 North Sea flood page.
2. September 1968. The East Dock Sewer overflowed in heavy rain. In Tilbury alone 1,750 houses flooded, a further 950 were affected and Dock Road was shut for four days (Level 1 SFRA).
3. 1972 to 1983. The storage area north of the town was built in 1972, the Tilbury Barrier went in across the dock entrance in 1981, and the raised Thames walls were complete for the winter of 1982 to 1983.
4. 1993 to 2012. Residents of Quebec Road reported flooding in September 1993, July and December 1994, March 1996, April 1998, three times in 2002 and 2003, and six times in 2011 and 2012.
5. December 2002 to January 2003. The strategy lists flooding in Tilbury, and at Bulphan, over the winter.
6. 2013. Anglian Water and the Environment Agency logged nine more incidents on Quebec Road. The council's Section 19 investigation (November 2013) found a silted outfall on the East Dock Sewer and an impaired sewer network, with homes on the west side flooded inside.
7. 2014. The 2015 strategy records flooding in Tilbury in 2014, the latest incident it lists for the borough.
8. January 2021. Work started on the dual-function lock gates at the dock entrance to replace the Tilbury Barrier.

Quebec Road shows a pattern that recurs across the town: four bodies share one drainage path, with Anglian Water's sewer running into a main river on port land that the Environment Agency maintains, all managed by the council as flood authority. A drainage strategy for a Tilbury site has to show where its water goes once that path is tide-locked. The mechanics of surges are in our storm surge explainer.

Clay, chalk and tide-locked sewers: the ground beneath a Tilbury drainage strategy

Infiltration is rarely the answer on the marsh. The ground is river alluvium over chalk, the council's strategy describes the reclaimed marsh as often saturated, and the sewers that would take the overflow already have a flooding record. A drainage strategy here usually stores water on site and lets it out slowly, at a rate the council will accept.

Our ground conditions and soakaway map gives a first view of the geology under a site, and the drainage calculators estimate greenfield runoff and storage. Under draft Policy DMP29 major development must achieve greenfield runoff rates, and where it cannot the council will seek a payment in lieu as well as the best rate the site can reach. Our guide to the 2025 National Standards for sustainable drainage covers the national rules behind it.

Which flood policies does a planning application in Tilbury have to meet?

Three layers apply. National policy sets when an assessment is needed and how the sequential and exception tests work. Thurrock's adopted Core Strategy still governs decisions, and the new Thurrock Local Plan, now at its final consultation stage, sets out the detailed floor level and drainage rules the council intends to apply. The council's flood studies supply the evidence for all three.

The sequential test applies to new homes and most other new development in Zones 2 and 3 unless the site is allocated and its risk has not changed, and PMD15 asks for each site's breach hazard rating to be part of the comparison. Our explainer on the sequential and exception tests covers both. Thurrock is its own lead local flood authority, so the drainage strategy goes to the council's flood team, not to Essex County Council.

Local government reorganisation does not change any of this yet. The Government confirmed five new unitary councils for Greater Essex in March 2026, but withdrew that decision on 7 September 2026 pending a national review, and Thurrock Council remains the planning and flood authority. Our note on reorganisation and flood risk follows the national picture.

The port, Tilbury2 and Tilbury3: building on defended marsh

Most new floorspace near Tilbury is port and logistics development on land behind the river wall, and most of it lies in Flood Zone 3. The draft Local Plan protects the port's land for port use and allocates further land east of the town, while housing comes forward on smaller sites in and around the old town and at Chadwell St Mary and East Tilbury.

• The port. Policy PP05 safeguards the Port of Tilbury, Tilbury2 and Tilbury3 for port operations; the port, which has traded since 1886, is part of the Thames Freeport. Warehouses there are less vulnerable uses, so the exception test does not normally apply, but the sequential test, breach levels, safe access for staff and drainage all do.
• Tilbury3. Allocation SS07 covers about 58 ha east of Tilbury2 for container handling, storage and distribution, an aggregates terminal and lorry parking, with a new road from Windrush Way. The allocation asks for a site-specific flood risk assessment and drainage dealt with on site.
• The football ground at Chadfields. Allocation NS21 proposes about 112 homes on the Tilbury Football Club site once the club moves, on condition that no flood storage capacity is lost from the Tilbury Flood Storage Area. The draft Level 2 study takes a firmer line: it says 51 per cent of the site should be kept for flood storage and does not consider the site suitable for housing. Applicants should expect that conflict to be tested.
• Other storage-area sites. The same study says two employment sites put forward off Marshfoot Road also lie in the storage area and should not be taken forward.
• The riverside. Policy PP06 supports reuse of the Grade II cruise terminal and riverside station building and a pontoon for a ferry to Kent and a river bus to London. Work on the river frontage meets the defences directly.
• The Lower Thames Crossing. Development consent was granted on 25 March 2025, as Medway Council reported. The SFRA describes compensatory flood storage and changes to the West Tilbury Main north of the town to deal with the tunnel approach.

For the three housing sites it assessed in the old town, the Level 2 study's message is consistent: none is shown to flood from overtopping in its design tide, but each is at residual risk from a breach and needs a safe place of refuge above the extreme flood level. That refuge, and the floor levels set by the SFRA and DMP29, shape the layout of a residential scheme long before the elevations are drawn.

From an extension off Dock Road to a warehouse by the lock: what a flood risk assessment in Tilbury covers

The type of scheme and its vulnerability class decide how much the report has to do. The table gives the usual position for a site in Flood Zone 3 in Tilbury; a site in the storage area or on the riverfront needs more.

Floor levels are where most Tilbury schemes need care. DMP29's 600 mm rule and the SFRA's tidal freeboard standard are separate tests, and the report has to show both are met, or explain why an extension cannot match them. Our flood risk vulnerability classification guide shows where each use falls, and our guide to converting a house into flats covers that case in detail.

Reports for sites behind Tilbury's river wall

Each report below answers a different question about a Tilbury site: whether it is safe, whether it should be built there, or where its rainwater goes.

• Applications behind the wall. Thurrock Council asks for a flood risk assessment for planning with any application in Zones 2 or 3, which in Tilbury means almost every site, and draft Policy DMP29 adds the floor level and drainage tests.
• Tide, rain and the storage area together. A flood risk assessment for a Tilbury site weighs a breach of the Thames walls, tide-locked drains, sewer flooding and, near Chadfields, the storage reservoir, and sets floor levels and refuge from them.
• Buying in the RM18 streets. When a search flags a house in the old town or near Quebec Road, a flood risk survey for property purchase looks at that building's floor level, the breach depths and its drainage history before exchange.
• Homes on unallocated land. New homes in Tilbury's Zone 3 usually need a sequential and exception test, run against the council's sites and the wider area of search, alongside the assessment.
• Water that cannot leave at high tide. A drainage strategy for a Tilbury scheme has to store rain while the sluices are shut and release it at a rate the council and Anglian Water will accept.
• Greenfield rates on the marsh. Major schemes must reach greenfield runoff rates under DMP29, and a surface water drainage strategy shows how, with storage in place of soakaways that the alluvium will not support.
• Conditions on a consent. Where a Thurrock permission comes with a drainage or maintenance condition, discharge of drainage conditions supplies the detailed calculations, layout and management plan the flood team asks for.
• Refuge when a surge is forecast. Homes at residual breach risk need a place of safety above the extreme flood level and warehouses need staff moved in time, and a flood warning and evacuation plan sets out both against the Shellhaven to Tilbury warnings.
• Breach levels for one site. Where the SFRA's borough-wide breach maps are too coarse for a large scheme on the Tilbury marshes, flood modelling sets depths, hazard and floor levels for that site.
• Port and logistics land. Before buying or leasing land around Tilbury2, Tilbury3 or Thurrock Park, flood risk due diligence sets out the zone, the breach hazard and the storage-area and drainage constraints.
• Firms inside the warning area. Logistics and port businesses behind the wall sit in the Shellhaven to Tilbury warning area, and a business continuity flood risk assessment plans for stock, staff and reopening after a surge or a drainage flood.
• New warehouses seeking credits. Large distribution buildings on the Tilbury3 allocation and the port's other land can earn the Pol 03 flood and surface water credits with a BREEAM flood risk assessment.
• Homes in Zone 3 with a flood history. Where cover or premiums are a problem for a house in Tilbury's old town or near Quebec Road, a flood risk assessment for insurance sets out the real risk to that property, defences and drainage included.
• Sewers with a flooding record. Anglian Water's records show repeated sewer flooding in Tilbury, so a foul drainage strategy shows the network can take a new scheme's flows or what has to change.
• Allocated and promoted land. For land put forward in the new Local Plan around Tilbury, East Tilbury and Chadwell St Mary, a flood risk feasibility study shows early whether the storage area, Zone 3b or breach depths limit what can be built.

Who to call when the river or the drains overflow in Tilbury

If floodwater puts anyone in Tilbury in danger, ring 999; a power cut caused by flooding goes to 105. The bodies below share the job of managing flood risk in the town.

Sandbags are not handed out in advance: the council issues limited supplies case by case during flooding, and owners are expected to protect their own homes and businesses. Signing up for Environment Agency warnings for the Shellhaven to Tilbury area is the quickest way to hear of a surge.

Questions about Tilbury sites, the gates and the storage area

Call 01293 214444 or email enquiries@unda.co.uk with the address of a house off Dock Road, a unit by the docks or a plot in Chadwell St Mary, and one of our consultants at Unda Consulting Limited will tell you which reports it needs. Neighbouring towns are on our Grays and Gravesend pages, across the river, and on our areas list.