Flood Risk Assessment in Cranleigh
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A flood risk assessment in Cranleigh is mostly about water that has nowhere to soak away. The village stands on Weald Clay, the Littlemead Brook runs westwards through it, and Cranleigh Waters curves round its southern and western edges towards Bramley, so rain that falls on a new roof, road or garden has to be led somewhere at a pace the brooks and ditches can take. Our consultants prepare flood risk assessments in Cranleigh for planning applications, buyers, lenders and insurers, together with sequential and exception tests and surface water drainage strategies.
On this page Cranleigh means the built-up village mapped by the Office for National Statistics: the High Street and the common, the estates north towards Barhatch Road and Summerlands, the housing east along Ewhurst Road, and the newer streets between the High Street, Alfold Road and Knowle Lane. All of it lies in the GU6 postcode district. Elmbridge Village to the west and Rowly to the north are counted as separate built-up areas, though both sit in Cranleigh parish. Waverley Borough Council decides planning applications here, and Surrey County Council is the Lead Local Flood Authority.
On Christmas Eve 2013 the Littlemead Brook rose to 3.38 m at the Cranleigh gauge, its highest recorded level, the day after the Environment Agency had warned 63 properties along Cranleigh Waters.
To talk through a plot anywhere in Cranleigh, call our flood risk consultants on 01293 214444 or email enquiries@unda.co.uk.
What Surrey's Section 19 report found in Cranleigh after Christmas 2013
Surrey County Council's Section 19 report for Waverley, published on 29 October 2015, names Cranleigh among the places in the borough where homes flooded inside and roads closed in the winter of 2013 to 2014. Its Cranleigh sub-area takes in the village, Ellen's Green and Rowly, and records what flooded and why.
- Eight homes from one brook. The worst flooding came when the Holdhurst Brook overflowed and flooded eight properties. A blocked trash screen at the entrance to a culvert made it worse, and runoff from nearby roads added to it.
- Elmbridge Road. Further homes flooded inside around Elmbridge Road, from Cranleigh Waters and from water spilling out of the disused Wey and Arun Canal.
- A warning at 22:03. The Environment Agency issued its flood warning for Cranleigh Waters near Cranleigh and Shamley Green at 22:03 on 23 December 2013, to 63 properties, and sent flood data recorders to the village in January 2014.
- Clay that will not take the water. The report describes the sub-area as underlain by impermeable clay, so rain runs off quickly instead of sinking in, although land beside the watercourses can see groundwater at the surface.
- Banks cleared and a grille to own. Waverley cleared the banks of Cranleigh Waters around Elmbridge Road with the Environment Agency and riparian owners, and began working with the county council to establish who owns and maintains the drainage asset known as the Nightingales Grill.
The report counts only flooding that people reported, and in October 2018 the Cranleigh Flood Forum heard the county council say it still needed better records of property flooding in the village. For an applicant, that makes any culvert, grille or ditch on or beside the site part of the flood risk, and Neighbourhood Plan policy CRAN14 now expects existing ditches and culverts to be kept. Our guide to Section 19 flood investigations explains when a council has to carry one out.
Screening a GU6 postcode before you buy or apply
Enter a postcode in the map below to screen it against Environment Agency data for rivers, surface water and reservoirs, or open our full flood risk map for any address in England. The coral line traces the Cranleigh built-up area. Godalming and Guildford lie downstream on the Wey, which Cranleigh Waters joins beyond Bramley, and Horsham is about 14 km to the south-east across the Sussex border. Treat the result as a first look: on clay, the surface water layer often matters more than the river zones.
Brooks, clay, sewers and a canal: how water reaches land in Cranleigh
Cranleigh's flooding comes from a cluster of small watercourses. Waverley's current Level 1 Strategic Flood Risk Assessment, published by AECOM in November 2018, treats the Holdhurst Brook, Littlemead Brook and Nuthurst Stream as main river tributaries of Cranleigh Waters, and puts parts of Cranleigh in Flood Zones 2 and 3 from Cranleigh Waters, the Nuthurst Stream and the Littlemead Brook. The July 2015 study it replaced traces Cranleigh Waters from just north of Ewhurst, south of the village and then north-west to Bramley and Wonersh, about 24 km in all, and lists Cranleigh among the places in the borough with the most documented flooding from any source.
| Source | Where in or around Cranleigh | Evidence |
|---|---|---|
| Littlemead Brook | Westwards through the village, past the low ground south of the High Street, to Cranleigh Waters | Environment Agency gauge at Cranleigh: usual range 1.23 m to 2.33 m, highest 3.38 m on 24 December 2013; property flooding possible above 3.81 m |
| Cranleigh Waters | South and west of the village, past Elmbridge Road and on to Bramley | Main river; gauge at Flash Bridge highest 3.95 m on 5 November 2000; homes on Elmbridge Road flooded inside in winter 2013 to 2014 |
| Smaller brooks | The Holdhurst Brook; Cobblers Brook and Thornhurst Brook, both crossed by Horsham Road; the Nuthurst Stream south of the High Street | Main river tributaries of Cranleigh Waters (2018 SFRA); eight properties flooded from the Holdhurst Brook in 2013 to 2014 (Section 19 report); the Local Plan asks for a buffer to the Nuthurst Stream |
| Surface water | Rye Farm on the B2130, by Cranleigh C of E Primary and Glebelands schools, Rowland Road, Summerlands and The Riding | Named as surface water locations in the 2015 SFRA; Nightingales and The Ridgeway were Christmas 2013 hotspots |
| Sewers | The combined and foul network across the village | The 2018 SFRA names Cranleigh (GU6 8), with Farncombe and Farnham, as where Waverley's reported sewer flooding is concentrated |
| Groundwater | Low land beside the watercourses | Historic records in the 2010 SFRA include Cranleigh; the 2018 SFRA maps elevated risk near Utworth Manor west of the village; the Section 19 report finds potential for it to reach the surface beside the watercourses, not across the clay |
| Canal and ponds | The disused Wey and Arun Canal west of the village; Vachery Pond to the south-east | Canal overflow at Elmbridge Road in 2013 to 2014; a breach at Vachery Pond would mostly follow the Cranleigh Waters floodplain down to Bramley, with little development in its path (2018 SFRA) |
Because the clay holds water at the surface, the Neighbourhood Plan describes Cranleigh as vulnerable to every source at once, with the sewer network quickly overwhelmed in heavy rain. Many plots border a ditch or brook that is an ordinary watercourse, where works need ordinary watercourse consent from Surrey County Council. Our pages on the Littlemead Brook and Cranleigh Waters follow each channel beyond the village, and the River Wey page picks up where Cranleigh Waters ends.
Cranleigh's flood record, 1968 to 2016
The Environment Agency describes Cranleigh as a flashy catchment, where the brooks rise quickly after heavy rain, and the same places flood again. The dates below come from the SFRA, the Section 19 report, the Environment Agency's gauges and the Neighbourhood Plan's flood risk evidence.
- 15 and 16 September 1968. Two days of heavy rain caused considerable flash flooding in the centre of Cranleigh from surface runoff, and Cranleigh Waters flooded along its whole length; flood alleviation works followed. The 2015 SFRA judges the event to have been about a 1 in 100 year flood, and residents told the Neighbourhood Plan that the floodplain was completely under water. Our article on the 1968 flood covers the storm itself.
- December 1979 and June 1981. Repeated flooding of the High Street and its shops, recorded in press cuttings gathered for the Neighbourhood Plan. Waverley built flood relief works after an engineering assessment in 1981 and 1982.
- November 2000. Cranleigh Waters reached 3.95 m at Flash Bridge on 5 November, still the highest level recorded there, and the Littlemead Brook spilled onto its floodplain.
- 23 and 24 December 2013. The Neighbourhood Plan's evidence records 56.8 mm of rain in one day; the Littlemead Brook peaked at 3.38 m, homes flooded and main roads became impassable.
- January and June 2016. Two more episodes of significant flooding, listed in the Neighbourhood Plan as the most recent.
You can follow the brooks as they rise on our live river levels map. The Environment Agency's Littlemead Brook gauge at Cranleigh and Cranleigh Waters gauge at Flash Bridge show the current level against the usual range and the thresholds at which land and then property can flood.
Local Plan policies CC4 and SS5, and Neighbourhood Plan policy CRAN14
Applications here are judged against chapter 18 of the August 2026 NPPF, Waverley's Local Plan Part 1, adopted in February 2018, and the Cranleigh Neighbourhood Plan for 2021 to 2032, which was made on 15 July 2024 after a referendum on 20 June. Policy F4 of the NPPF sets when a site-specific assessment is needed, F5 and F6 set the sequential and exception tests, and F8 expects sustainable drainage to meet the 2025 National Standards.
| Policy | Plan | What it asks of a Cranleigh scheme |
|---|---|---|
| CC4 Flood Risk Management | Local Plan Part 1 (2018) | Development safe, risk not increased elsewhere and residual risk managed; at-risk sites located sequentially, with a site-specific flood evacuation plan where the tests are passed; no loss of floodplain flow or storage; SuDS on major schemes; no increase in the volume or rate of runoff; no off-site property or highway flooding up to the 1 in 100 year storm with climate change |
| CC1 Climate Change | Local Plan Part 1 (2018) | Support for flood storage capacity, built-in resilience and green infrastructure and SuDS that reduce surface water runoff |
| ALH1 The Amount and Location of Housing | Local Plan Part 1 (2018) | At least 1,700 new homes in Cranleigh parish over the plan period, counting homes built or permitted since April 2013 |
| SS5 Land South of Elmbridge Road and the High Street | Local Plan Part 1 (2018) | Around 765 homes and a country park on 62 hectares; building focused on Flood Zone 1; an FRA showing safe access and egress; a managed buffer to the Littlemead Brook and the Nuthurst Stream; the reservoirs on the western part kept |
| SS4 Land at Horsham Road | Local Plan Part 1 (2018) | Around 250 homes, keeping the site's ponds, ditches, trees and hedgerows |
| CRAN14 Flood Risk and Drainage | Cranleigh Neighbourhood Plan (2024) | Surface water drainage details including gully maintenance, SuDS and lifetime management; natural flood alleviation where possible; existing ditches and culverts kept; sewerage capacity in place so sewer flooding risk is minimised |
| CRAN17 Water Supply and Wastewater Infrastructure | Cranleigh Neighbourhood Plan (2024) | Water-efficient design, with new homes using no more than 105 litres per head per day |
The Neighbourhood Plan explains why CRAN14 exists. Much recent building, it says, has gone onto Cranleigh's natural floodplain south of the High Street, where the SuDS installed are untested in heavy rain, so they should be verified by the Lead Local Flood Authority once complete. The plan requires SuDS on major development and encourages them for any new floorspace other than a householder extension. Within SS5, permission followed for 425 homes east of Alfold Road in March 2016 and 75 at Little Meadow in July 2016, with outline consent for 265 at Knowle Park, between Knowle Lane and Alfold Road, in March 2017. The Level 1 SFRA in use is AECOM's of November 2018, which replaced the July 2015 study cited in the Local Plan, and a Level 2 SFRA of August 2016, updated that December, tested the sites with flood risk. Waverley's new Local Plan is timetabled for adoption in January 2029, and its flooding evidence page has no study on it yet.
The authorities are changing. On 1 April 2027 Waverley and five neighbouring boroughs, together with Surrey County Council's services in the west of the county, pass to a new West Surrey Council; until then the existing councils carry on as usual. Our article on local government reorganisation looks at what the move means for flood risk and planning.
Surrey's drainage rules for a site on the Weald Clay
As Lead Local Flood Authority, Surrey County Council reviews the surface water drainage on every major application in Cranleigh, and its SuDS guidance sets out what it expects, written to the 2025 National Standards and the August 2026 NPPF. On the clay, the rules below shape most schemes.
- Rainwater reuse always. Surrey is a water-stressed area, so the first priority of the national hierarchy, collecting rainwater for non-potable use, is always required, usually alongside an outfall. Our article on rainwater harvesting in SuDS shows how the two are combined.
- Test before ruling out infiltration. Where test results are missing, the county asks for a reason and a desk study of the ground. On Cranleigh's clay a BRE 365 infiltration test often fails, and the result is the evidence for moving down the SuDS hierarchy.
- Held to the 1 in 2 year rate. For most sites that add runoff, the allowable discharge is limited to the 50% annual exceedance probability rate, so attenuation storage has to hold the difference up to the design storm.
- Prove the ditch can cope. Discharge to a watercourse has to show the channel's onward connectivity, condition and capacity, which on a Cranleigh site may mean surveying a ditch or culvert well beyond the boundary.
- Nothing into the highway drains. New private surface water may not discharge onto the road or into the highway drainage system, and an exceedance plan must show no increase in flood risk on or off the site.
The county is not a statutory consultee on groundwater, so any high water table beside the brooks has to be dealt with in the application's own evidence. Our geology and ground conditions map gives a first indication of the ground before a trial pit is dug, and our explainer on an LLFA objection covers the usual reasons a drainage case is sent back.
Building on clay south of the High Street?
Send us the address and a few lines on the scheme, from one new house to a phase of an allocated site. One of our experienced flood risk consultants will reply within 60 minutes with a free, no-obligation quote.
Start a QuoteExtensions, infill plots and allocated phases: does a Cranleigh scheme need an assessment?
In Flood Zones 2 and 3, along the Littlemead Brook and Cranleigh Waters, almost every proposal needs an assessment. Away from them the trigger is usually size or surface water, and on Cranleigh's clay surface water reaches a long way from the brooks. The table gives the usual position for each kind of scheme; the Flood Map for Planning and the SFRA mapping settle it for a given plot.
| Proposal | Where | What applies |
|---|---|---|
| House extension | Flood Zone 2 or 3 beside the brooks | An assessment is needed; a minor extension can use the Environment Agency's standing advice, and the sequential test does not apply |
| New house or infill plot | Flood Zone 2 or 3 | An assessment and a sequential test, and the exception test where the vulnerability calls for it |
| New house or infill plot | Flood Zone 1 inside a mapped surface water flow path | An assessment of that risk under NPPF policy F4, with the drainage set out under CRAN14 |
| Ten or more homes | Any zone | A surface water drainage strategy reviewed by Surrey County Council, plus an assessment where a zone, size or other source triggers one |
| Site of 1 hectare or more | Flood Zone 1 | An assessment under national policy and CC4, with the drainage strategy |
| Phase of an allocated site | SS4 or SS5 land | The allocation's own tests: building on Flood Zone 1, safe access and egress, buffers to the brooks, ponds and reservoirs kept |
| Change of use to homes | Flood Zone 2 or 3 | An assessment proportionate to the more vulnerable use |
Access needs checking whatever the zone. Elmbridge Road, the main route out to the A281, is single track for a long stretch where it crosses Cranleigh Waters and the old canal, and the Neighbourhood Plan notes that it floods in heavy rain. For extensions, our guide to building an extension in a flood zone explains the standing advice route, and planning with Environment Agency standing advice sets out what it covers.
Sewage capacity and the works on Elmbridge Road
Thames Water's records in the 2018 SFRA show 151 sewer flooding incidents across Waverley in 20 years, 19 of them in the GU6 8 sector. Cranleigh's sewage treatment works on Elmbridge Road discharges into Cranleigh Waters and also serves parts of Alfold, Dunsfold and Ewhurst. The Neighbourhood Plan records that some new estates rely on pumping stations with storage tanks that release sewage only when the network has room, and that Thames Water expects the works to cope with the Local Plan's growth only after a phased and funded upgrade. Notes of the parish council's meeting with Thames Water in November 2022 put its capacity at 107 litres a second, with an upgrade planned to 144 litres a second and the flow work then due by March 2025.
For a drainage case this matters twice. Surface water must stay out of the foul network, which the plan calls the major contributor to sewer flooding, and a scheme of any size needs Thames Water's view on foul capacity early. Our guides to sewer flooding and to water companies in the planning process cover what to ask.
Reports our consultants prepare for sites from the High Street to Knowle Lane
We prepare reports in Cranleigh for landowners, developers, architects, home buyers and insurers. Each row below answers a separate question, and on a plot beside the Littlemead Brook several go in together.
- Every source on one plot. A flood risk assessment weighs the brooks and Cranleigh Waters against surface water off the clay, the sewers, the canal and any culvert on the boundary.
- Applications under CC4. A flood risk assessment for planning answers policy CC4, the allocation tests in SS4 and SS5, CRAN14 and NPPF policy F4.
- Buying near the brooks. Before exchange, a flood risk survey for property purchase looks at the house, its floor levels and how its street fared in 2013 and 2016.
- Homes in Zone 2 or 3. New homes on flood zone land need a sequential and exception test alongside the assessment, as CC4 requires.
- Runoff from clay. A drainage strategy shows where water goes when soakaways fail, with rainwater reuse built in.
- Major schemes. A surface water drainage strategy meets Surrey County Council's guidance, the 1 in 2 year discharge limit and the 2025 National Standards.
- After permission. Discharge of drainage conditions supplies the drainage detail, verification and maintenance plan that a Cranleigh condition asks for.
- Where the outlines run out. The 2018 SFRA maps climate change on Cranleigh Waters only to the 2040s, against the 2080s elsewhere on the Wey, so flood modelling can test the brook beside a site over its full lifetime.
- A way out in a flood. Policy CC4 asks for a site-specific evacuation plan where at-risk development passes the tests, which a flood warning and evacuation plan provides.
- Wet ground by the brooks. The Section 19 report finds potential for groundwater to reach the surface beside Cranleigh's watercourses, and there a groundwater flood risk assessment sets a level for floors, storage and below-ground structures.
- Cover after a claim. For homes that flooded in 2013 or 2016, a flood risk assessment for insurance sets out the house's floor levels and history for an underwriter.
- Limited sewage capacity. While capacity at the Elmbridge Road works is upgraded, a foul drainage strategy shows how a scheme's wastewater will be handled.
- Land not yet allocated. With 1,700 homes set for the parish and a new Local Plan in preparation, a flood risk feasibility study tests land before it is promoted.
Reporting flooding in Cranleigh, from a blocked culvert to the sewage works
Anyone caught by rising water on Elmbridge Road or anywhere else in the village should call 999, and a power cut during a flood is reported on 105. For everything short of an emergency, the bodies below each deal with a different part of the problem.
| Body | Role in Cranleigh | Contact |
|---|---|---|
| Emergency services | Floodwater putting anyone in danger | 999 |
| Electricity network operators | Power cuts during flooding | 105 |
| Environment Agency | Cranleigh Waters and its main river tributaries, including the Littlemead Brook; the alert and warning areas; planning consultee in Flood Zones 2 and 3 | Floodline 0345 988 1188; Cranleigh Waters flood alert area |
| Surrey County Council | Lead Local Flood Authority for surface water, groundwater and ordinary watercourses; highway authority; drainage consultee on major schemes | Report flooding; flooded roads 0300 200 1003; SuDS@surreycc.gov.uk |
| Waverley Borough Council | Planning authority until 31 March 2027; land drainage powers shared with the county council | Cranleigh Neighbourhood Plan |
| Thames Water | Water supply and sewerage, including the Elmbridge Road treatment works | Sewer flooding |
| Thames Regional Flood and Coastal Committee | Approves flood and coastal investment across the Thames catchment, which includes the Wey | Thames RFCC |
| Surrey Local Resilience Forum | Emergency planning by the county's councils, emergency services, Environment Agency and utilities | Surrey LRF |
| Cranleigh Parish Council | Emergency planning at parish level; publishes the notes of the Cranleigh Flood Forum, where residents meet the county, the borough, the Environment Agency and Thames Water; not a planning authority | Through the parish council office |
Sign up for free flood warnings for the Cranleigh Waters warning area near Cranleigh and Shamley Green, which includes Elmbridge Village, and check the Environment Agency's Cranleigh flood risk summary for current alerts. Surrey's Local Flood Risk Management Strategy, first published for 2017 to 2032 and refreshed in 2025, sets out how the county and its partners manage local flooding.
Cranleigh flood risk questions from buyers, builders and landowners
Does a Cranleigh application need a flood risk assessment if the plot is well away from the brooks?
In two common cases, yes. A plot in Flood Zone 1 still needs one if it covers a hectare or more, or if surface water mapping shows a flow path across it, which on Cranleigh's clay is common. A major scheme also needs a surface water drainage strategy that Surrey County Council will review, whatever its zone.
Why does a flood risk assessment beside the Littlemead Brook cost more than one on higher ground in Cranleigh?
Because there is more to establish. A plot by the brook may need its flood levels taken from a model or a survey, floor levels and a dry route out set, and the culverts and ditches downstream checked. A plot on higher ground is usually a shorter report on surface water and drainage. We quote a fixed fee, free, once we have the address and the proposal; our guide to flood risk assessment costs explains what drives it.
Does Waverley or Surrey County Council check the drainage on a Cranleigh application?
Both have a part. Waverley Borough Council decides the application, and Surrey County Council, as Lead Local Flood Authority, advises it on surface water drainage for major schemes. The Environment Agency comments on sites in Flood Zones 2 and 3 beside Cranleigh Waters. From 1 April 2027 the new West Surrey Council takes over the work of both councils.
Which streets in Cranleigh have flooded?
The records name the High Street, which flooded repeatedly in 1979 and 1981, and Elmbridge Road, where homes flooded from Cranleigh Waters and the canal in the winter of 2013 to 2014. That winter the Holdhurst Brook flooded eight properties, and Nightingales and The Ridgeway were hotspots. Waverley's 2015 SFRA also lists Rye Farm on the B2130, Rowland Road, Summerlands and The Riding for surface water.
Is Cranleigh Waters a main river, and what does that change for a site beside it?
Yes, and Waverley's 2018 SFRA treats the Littlemead Brook, Holdhurst Brook and Nuthurst Stream that feed it as main rivers too. The Environment Agency is responsible for them, comments on development in their flood zones and runs the alert and warning areas. The ditches and culverts across the village are ordinary watercourses, where Surrey County Council gives consent for works. A flood risk assessment establishes which applies on each boundary.
Can a soakaway drain a new house in Cranleigh?
Rarely on its own. The Neighbourhood Plan says much of Cranleigh lies on heavy clay that is unsuitable for infiltration. A BRE 365 test is still needed, because Surrey County Council asks for evidence before infiltration is ruled out, but most schemes end up storing runoff and releasing it slowly to a ditch or brook.
What discharge rate will Surrey County Council accept from a Cranleigh scheme?
For most sites that add runoff, the county limits the allowable discharge to the 1 in 2 year rate, and asks for the lowest achievable rate where Thames Water sets a lower figure. It always expects rainwater to be collected for reuse, because Surrey is water-stressed, and it wants proof that the receiving ditch or brook can take the flow.
What can lengthen a flood risk assessment for a Cranleigh site?
Surveys and replies from other bodies. A plot beside the brooks may need a topographic survey, flood level data from the Environment Agency or a model of the brook, and a scheme with new drains may need infiltration tests and Thames Water's response on foul capacity. Starting those early keeps the report on track for a submission date.
Should I buy a house in Cranleigh that sits in a flood risk area?
Check before you commit. Screen the postcode on the map above and the government's long-term flood risk service, then ask the seller whether the house flooded in December 2013 or in 2016, inside or in the garden, and whether it has made a claim. A pre-purchase flood survey looks at the building itself; our guide to checking flood risk before buying lists the questions.
Can a householder in Cranleigh complete their own flood risk assessment for an extension?
The Environment Agency's standing advice lets the owner of a minor extension in Flood Zone 2 or 3 set out floor levels and flood resilience measures without a full report. It does not cover a culvert under the garden, a surface water flow path or a brook that has flooded the street, so where any of those apply a professional assessment is the safer course.
Exchanging, applying or discharging a condition in Cranleigh?
Tell us the address, what you plan and any date you are working to. One of our experienced flood risk consultants will come back within 60 minutes with a free, fixed-fee quote, with no obligation.
Start a QuoteUnda Consulting Limited is a CIWEM Business Partner, our flood risk consultants are chartered, and every report is signed off by a senior consultant before it goes to Waverley or to a buyer. For a site in Cranleigh or the villages around it, call 01293 214444 or email enquiries@unda.co.uk. For the wider county, see our page on flood risk in Surrey, or browse all the areas we cover.
