When a scheme needs environmental impact screening

The EIA screening threshold residential developers run into first is 150 dwellings, and the second is five hectares. Either one puts a housing scheme into Schedule 2 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, which means the local planning authority has to form a view on whether the scheme is likely to have significant effects on the environment before it can determine the application. Crossing a threshold does not make a scheme EIA development. It makes screening unavoidable.

That distinction matters commercially, because the cost difference between a screened-out scheme and an EIA scheme is measured in tens of thousands of pounds and several months of programme.

Which categories catch ordinary development

Schedule 1 projects always require assessment, and they are mostly heavy infrastructure: refineries, power stations, large chemical works, major waste installations. Housing and commercial schemes almost never appear there.

Schedule 2 is the one to read. Two categories do nearly all the work on ordinary development.

Category 10(b) is deliberately broad. A mixed-use block with 160 flats and ground floor retail is caught on the dwelling count alone. A 6 ha employment scheme is caught on area even if the buildings cover a fraction of it. And a phased development should be assessed as a whole rather than sliced into sub-threshold parcels, because the courts have treated salami-slicing as a misapplication of the Regulations.

Sensitive areas remove the thresholds entirely

This is the trap. Where the site is in a sensitive area, development of a Schedule 2 description is Schedule 2 development regardless of the column 2 threshold. A nine dwelling scheme inside a National Park is screenable. A single commercial building within a Site of Special Scientific Interest is screenable.

Sensitive area is defined in regulation 2 and covers Sites of Special Scientific Interest, National Parks, the Broads, National Landscapes, World Heritage Sites, scheduled monuments, Special Areas of Conservation and Special Protection Areas. Conservation areas, listed building settings and local wildlife sites are not sensitive areas for these purposes, although they stay material considerations in the ordinary way.

Check the designation before you assume a small scheme sits outside the regime. The constraint search done at acquisition stage should already tell you, and if it does not, that is a gap in the due diligence rather than a reason to proceed.

Requesting a screening opinion

You can ask the authority for a screening opinion before submitting an application under regulation 6. The request needs a plan sufficient to identify the land, a description of the development and its possible effects on the environment, and any information you hold on those effects.

The authority must adopt its opinion within three weeks unless a longer period is agreed in writing. If it misses that deadline or reaches a conclusion you consider wrong, regulation 7 allows a request to the Secretary of State for a screening direction, handled by the Planning Inspectorate. Authorities can also screen on their own initiative after an application arrives, which is the worst moment to find out.

A negative screening opinion is worth having in writing before you commission the rest of the evidence base. It is the document that tells your funder the scheme is not an EIA project.

How the decision is actually made

Schedule 3 sets the selection criteria, and a good screening request is structured around them rather than around the applicant's preferences. The three headings are the characteristics of the development, its location, and the types and characteristics of the potential effects.

In practice the authority will focus on a handful of issues: traffic generation and its effect on air quality, surface water and flood risk, effects on designated sites and protected species, loss of agricultural land, heritage assets, and cumulative effects alongside other committed development. The last of these catches more schemes than any other single factor, because a 140 dwelling site next to a consented 200 dwelling site is not assessed in isolation.

Screening asks whether the environmental effects are likely to be material enough to warrant formal assessment. Officers who are nervous about a scheme sometimes screen it in to buy themselves a fuller evidence base. The counter to that is a screening request that already explains how each potential effect will be assessed and mitigated through standalone reports, so that an environmental statement adds process rather than information.

What a positive screening actually changes

If the scheme is EIA development, five things follow.

1. An environmental statement is required, and under regulation 18 it must be prepared by competent experts. This is a legal requirement, not a preference. An Environmental Impact Assessment draft can structure the chapters and marshal the policy, but the assessment itself must come from qualified specialists, and PlanScope's draft is a starting point for those experts rather than a substitute for them.
2. You should request a scoping opinion under regulation 15. It is optional, but proceeding without one on a contested site is a false economy.
3. The determination period becomes 16 weeks rather than 13 for a major application, and publicity runs for 30 days.
4. The application fee changes, and the authority may charge for the scoping opinion under its published schedule, so check the current fee position before budgeting.
5. The authority cannot lawfully grant permission without taking the environmental information into account, which gives objectors a judicial review route if the process is defective.

The programme consequence is larger than the cost. Survey seasons govern the ecology chapters, traffic counts have to fall in neutral months, and a scheme screened in during March often cannot submit until the following spring.

Timing the request in the programme

Screen early, and screen on a described scheme rather than a vague one. A request submitted on a red line boundary with no indicative capacity invites a cautious answer.

The sequence that works on most sites is this. Establish the constraint picture at acquisition. Fix an indicative capacity and access strategy. Commission a Preliminary Ecological Appraisal and a flood risk position, because those two drive most screening outcomes and both take time to arrange. Then submit the screening request with that evidence attached, and only afterwards commit to the full technical programme.

Where the dwelling count sits close to 150, the screening question becomes a design question. Dropping below the threshold does not avoid screening if the site exceeds five hectares or sits in a sensitive area, and a scheme designed around the number rather than the place tends to produce a worse application. Thresholds of this kind change several things at once, which is also true of the levy and obligation thresholds covered in our note on obligations at different scheme sizes, and of the referral thresholds in our note on Greater London Authority referable applications.

This is general guidance rather than legal advice. Check the position with your local planning authority or a qualified professional before relying on it, and read the current Regulations and Planning Practice Guidance on environmental impact assessment at the point of submission.

Browse all 66 PlanScope report types and start a draft to see which technical reports a major application needs alongside the screening request.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.