Environmental Impact Assessment
An Environmental Impact Assessment is the most comprehensive environmental review that can be required for a development project. Reserved for schemes with potentially significant environmental effects, the EIA process is governed by the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 and can take many months to complete. It is not something to undertake lightly.
Typical Cost
£300 – £5,000+
Turnaround
1 – 6 weeks
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What is a Environmental Impact Assessment?
An Environmental Impact Assessment (EIA) is a systematic process for identifying, predicting, and evaluating the likely significant environmental effects of a proposed development before planning permission is granted. The findings are presented in an Environmental Statement (ES), a substantial technical document that covers topics ranging from ecology and landscape to transport, air quality, noise, and socio-economics. The EIA process includes screening, scoping, baseline surveys, impact assessment, mitigation design, and public consultation.
When is a Environmental Impact Assessment required?
EIA is required for developments listed in Schedule 1 of the EIA Regulations 2017, which includes chemical installations, power stations, motorways, and large industrial facilities — these always require EIA regardless of their likely effects. Schedule 2 developments — such as urban development projects exceeding 5 hectares, industrial estates over 0.5 hectares, or housing schemes of 150 dwellings or more in sensitive areas — require EIA only if they are likely to have significant environmental effects. A screening opinion from the local authority determines whether EIA is needed for Schedule 2 projects.
What does a Environmental Impact Assessment include?
The Environmental Statement must include a description of the development and reasonable alternatives considered, a description of the baseline environment, an assessment of the likely significant effects on population and human health, biodiversity, land, soil, water, air, climate, material assets, cultural heritage, and landscape, a description of measures to avoid, prevent, reduce, or offset significant adverse effects, a non-technical summary accessible to the general public, and details of the assessment methodology, competence of experts, and any difficulties encountered.
How much does a Environmental Impact Assessment cost?
EIA is expensive. A screening opinion request typically costs £1,000 to £3,000 to prepare. If a full EIA is required, the cost of preparing the Environmental Statement depends heavily on the number of technical topics to be assessed and the complexity of the site. Small to medium EIAs for developments such as a 200-dwelling housing scheme might cost £30,000 to £80,000. Large-scale infrastructure or industrial projects can require Environmental Statements costing £100,000 to £500,000 or more, reflecting the specialist survey work, modelling, and expert input required.
Who can prepare a Environmental Impact Assessment?
The EIA process must be coordinated by a competent EIA practitioner, typically a chartered environmental consultant or planner with extensive EIA experience. The Environmental Statement draws on multiple specialist disciplines — ecology, air quality, noise, transport, heritage, landscape — each assessed by a qualified expert. The Institute of Environmental Management and Assessment (IEMA) maintains a register of EIA practitioners, and competence of the assessment team must be demonstrated within the Environmental Statement itself.
How long does a Environmental Impact Assessment take?
The EIA process is lengthy. Screening takes 3 to 5 weeks from the local authority. Scoping, which defines the topics to be assessed, takes a further 5 weeks for the statutory consultation period. Baseline surveys — particularly ecological surveys that are seasonally constrained — can take 6 to 18 months. Preparing the Environmental Statement once all surveys are complete typically takes 3 to 6 months. In total, expect the EIA process to take 12 to 24 months from start to submission.
Frequently Asked Questions
How do I know if my development needs an EIA?
Check whether your project falls within Schedule 1 or Schedule 2 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017. Schedule 1 developments always need EIA. For Schedule 2 developments, you can request a screening opinion from the local planning authority, who must respond within 3 weeks (though it often takes longer). The screening considers the nature, size, and location of the development and whether significant environmental effects are likely.
What is an EIA screening opinion?
A screening opinion is a formal determination by the local planning authority as to whether a proposed development is EIA development — that is, whether it is likely to have significant environmental effects requiring assessment. You submit a request with a plan and description of the development, and the authority issues a positive opinion (EIA required) or negative opinion (EIA not required). There is no fee for requesting a screening opinion, but preparing the supporting information usually requires professional input.
What is EIA scoping?
Scoping is the process of agreeing with the local authority which environmental topics need to be assessed in the EIA and which can be scoped out. A scoping request is submitted with a description of the development and preliminary environmental information. The authority consults statutory bodies and issues a scoping opinion within 5 weeks, setting out the topics that should be addressed in the Environmental Statement. Scoping is not mandatory but is strongly recommended as it avoids wasted effort on irrelevant topics.
Can I avoid EIA by splitting my development into smaller phases?
No. The EIA Regulations specifically address this through the concept of cumulative effects. If a development is artificially divided into smaller elements to avoid triggering EIA thresholds, the local authority can and should consider the project as a whole. This practice, known as 'salami slicing,' has been challenged successfully in the courts and is likely to result in enforcement action.
What is a non-technical summary?
The non-technical summary (NTS) is a plain-language version of the Environmental Statement intended for the general public and non-specialist readers. It must summarise the key findings, significant effects, and proposed mitigation measures in accessible language without technical jargon. The NTS is often the most widely read part of the Environmental Statement and is critical for public consultation. Planning committees frequently rely on it rather than reading the full ES.
How long does an Environmental Impact Assessment take?
The full EIA process typically takes 12 to 24 months. Ecological surveys alone can take a full year to cover all seasonal survey windows. After baseline data collection, preparing the Environmental Statement takes 3 to 6 months. The determination period for an EIA application is 16 weeks rather than the standard 8 or 13 weeks, so the overall timeline from inception to decision is considerably longer than for non-EIA applications.
What happens if I submit a planning application without EIA when one is required?
The application cannot be lawfully determined without the Environmental Statement. If the authority considers EIA is required, it must notify you and request submission of the ES. Any permission granted without EIA when one was required is liable to be quashed through judicial review. The Regulations are strict on this point, and there have been numerous successful court challenges where EIA was not carried out.
Do I need to assess alternatives in an EIA?
Yes. The EIA Regulations require the Environmental Statement to include a description of the reasonable alternatives studied by the developer and an indication of the main reasons for selecting the chosen option, including a comparison of environmental effects. This does not require you to assess every conceivable alternative, but you should demonstrate that reasonable alternatives — such as different sites, layouts, scales, or designs — were considered and explain why they were rejected.
What are cumulative effects in EIA?
Cumulative effects are the combined impacts of your development together with other existing and proposed projects in the area. The Environmental Statement must identify and assess these combined effects. For example, the traffic impact of your scheme alone might be acceptable, but when combined with three other permitted developments on the same road, the cumulative effect on congestion and air quality could be significant.
Can the EIA screening opinion be challenged?
Yes. If you disagree with a positive screening opinion (EIA required), you can request a screening direction from the Secretary of State. If a third party believes a negative opinion was wrongly issued, they can challenge it through judicial review. The courts have overturned screening opinions in both directions, so it is important that the local authority applies the Regulations correctly and gives adequate reasons for its decision.