Bat Surveys for Planning Applications in West Sussex

When councils ask for a bat survey

West Sussex councils do not use a single rule. Several name roofs, roof voids, conversions or demolition of older buildings, and ask for a survey where bats are likely to be present. The list below shows what each says; check your own council's current wording.

• Arun: modification, conversion, demolition or removal of buildings and structures, especially roof voids, where protected species are likely. As a general rule, farm buildings or dwellings surrounded by open space, woods or close to water should undertake bat roost and activity surveys.
• Chichester: conversions and demolition where bats may be present. If the appraisal identifies a need for further surveys, such as a bat emergence survey, those must be submitted too.
• Adur & Worthing and Worthing: any works within the roofs of buildings or demolition of older buildings (shared list); works to or demolition of a building or roofs (Worthing).
• Crawley: modification, conversion or demolition of buildings, especially roof voids, where protected species are likely.
• Mid Sussex: demolition, alteration or conversion of older or rural buildings needs a bat and owl survey and mitigation plan.
• Horsham: demolition of buildings is one example where a biodiversity survey report or PEA is needed.
• South Downs National Park Authority: a survey where there is a reasonable likelihood of protected species being affected.

The full comparison is on the home page table.

How bats are protected by law

All bat species are protected. Under the Wildlife and Countryside Act 1981 it is an offence to intentionally or recklessly disturb a bat in a roost or obstruct access to one. Under the Habitats Regulations 2017 it is also an offence to kill, injure or deliberately disturb bats, or damage a resting place. This is a summary, not legal advice.

• Wildlife and Countryside Act 1981. Section 9(4) makes it an offence to intentionally or recklessly damage or destroy a place a protected animal uses for shelter, disturb it there, or obstruct access to it. Schedule 5 lists all horseshoe and typical bats, but for bats only for the disturbance, obstruction and sale offences (section 9(4)(b) and (c) and (5)).
• Conservation of Habitats and Species Regulations 2017. All horseshoe and typical bats are European protected species (regulation 42 and Schedule 2). Regulation 43 makes it an offence to deliberately capture, injure or kill them, to deliberately disturb them, or to damage or destroy a breeding site or resting place.

We summarise the wording of the legislation only. Whether a particular project risks an offence is a matter for a qualified ecologist or a solicitor.

Preliminary roost assessment or emergence survey?

A preliminary roost assessment (PRA) looks at a building to judge its potential for roosting bats and can be done at any time of year. Dusk emergence surveys, where surveyors watch for bats leaving a roost, follow where the assessment finds bat potential, with visit numbers guided by the suitability rating. They run only in the bat season.

• PRA. The Bat Conservation Trust guidelines say a PRA can be carried out at any time of year if limitations are recognised and reported. Its result, a low, moderate or high suitability rating, guides the number of emergence visits.
• Emergence surveys. Presence or likely absence surveys include dusk visits, where surveyors watch, listen for and record bats exiting roosts. Dawn re-entry visits are no longer routinely recommended for presence or absence surveys. A survey only shows bat presence or absence at the time it is carried out.
• If bats are found. The next stage is roost characterisation surveys (BCT paragraph 7.2.41), depending on how much is already known about species, numbers and the type of roost.

Visits and season

The guidelines recommend one dusk emergence visit for low roost suitability, two for moderate and three for high. Surveys run within set months between May and September, and visits should be at least three weeks apart. Your ecologist sets the final number for your building.

Timing risk for a planning application

Because emergence surveys only run in the bat season, a building that needs them cannot be fully surveyed outside it. Arun and Chichester want surveys submitted with the application, so starting with a roost assessment gives more room to plan around the season.

Three visits spaced at least three weeks apart take at least six weeks, and the months are fixed. Chichester's 2018 guidance says surveys should be done before you submit to avoid delays, and Arun's list says further species-specific surveys must be submitted with the application.

A survey from an earlier season may still be usable: CIEEM's advice note says a report under 12 months old is likely to be valid in most cases, with councils free to apply their own limits. More on this in the home page FAQ. Not sure what your council wants? The preliminary ecological appraisal is usually the first step.

What a bat survey costs

Across the firms we checked, a bat preliminary roost assessment is listed from £350 to £895 plus VAT, and one firm lists emergence surveys from £525 per visit. No Sussex firm we checked publishes prices, so local costs are by quote. The cost page shows each firm and date.

See the full table of published ecology survey prices and what drives them.

Frequently asked questions

Short answers on roof works, whether a bat survey is a legal requirement, and whether surveys can be done in winter. They summarise the sources listed below; none is legal advice. Councils' wording varies, so check your own council's current list.

Sources and dates

Legal points come from legislation.gov.uk and timing from the Bat Conservation Trust guidelines. Council wording comes from each council's own validation document. All were accessed on the dates shown; check current versions before relying on them. Dates are given in each entry.

• legislation.gov.uk, Wildlife and Countryside Act 1981, section 9, accessed 9 November 2026.
• legislation.gov.uk, Wildlife and Countryside Act 1981, Schedule 5, accessed 9 November 2026.
• legislation.gov.uk, Conservation of Habitats and Species Regulations 2017, regulation 42 and Schedule 2, accessed 9 November 2026.
• legislation.gov.uk, Conservation of Habitats and Species Regulations 2017, regulation 43, accessed 9 November 2026.
• Bat Conservation Trust, Bat Surveys for Professional Ecologists: Good Practice Guidelines, 4th edition (2023), copy hosted by Mid Sussex District Council (paras 7.2.1 and 7.2.38; Tables 7.1 and 7.2), accessed 8 November 2026.
• CIEEM, Advice Note on the Lifespan of Ecological Reports and Surveys (April 2019), accessed 8 November 2026.
• Arun District Council, Planning application validation requirements (effective 17 October 2024), accessed 9 November 2026.
• Chichester District Council, Local Validation List, November 2023 (Word document linked from the council's apply page), accessed 9 November 2026.
• Chichester District Council, Guidance on Ecological Surveys and Planning Applications (March 2018), accessed 9 November 2026.
• Adur & Worthing Councils, Local Validation List, accessed 8 November 2026.
• Adur & Worthing Councils, Worthing planning application validation requirements (effective 1 April 2026), accessed 8 November 2026.
• Crawley Borough Council, National and local list of validation requirements (file dated March 2025), accessed 8 November 2026.
• Mid Sussex District Council, Validation Criteria (Local List) (council page last updated 15 September 2026), accessed 8 November 2026.
• Horsham District Council, Development Management Local Information Requirements for Validation (no date shown), accessed 9 November 2026.
• South Downs National Park Authority, Local List of Requirements for Planning Applications (BNG revision, March 2024), accessed 8 November 2026.