Health impact assessment thresholds and content
Establish whether an assessment is required, at what depth, and what the public health team expects, before writing anything. Thresholds, determinants and securing mitigation.
No statute requires a health impact assessment for an English planning application. The requirement comes from the local plan, and the health impact assessment threshold it sets is usually expressed in dwellings or floorspace, commonly somewhere between 50 and 150 homes with a lower trigger inside an area of poor health outcomes.
That means the first task is not writing the assessment. It is establishing whether one is required at all, at what depth, and whether the council's public health team expects to be consulted before submission.
Where a health assessment is required
Three sources create the requirement.
Local plan policy is the main one. Many authorities carry a development management policy requiring a health impact assessment for major development, sometimes with a numerical threshold and sometimes qualified by location, for instance any scheme within a ward in the most deprived national quintile.
Validation lists are the second. A council can require the assessment as a local validation requirement, in which case its absence makes the application invalid rather than merely weak.
The third is the London Plan, which sets an expectation that development proposals should promote health and reduce health inequalities, with boroughs adding their own thresholds and formats. Referable schemes face the question twice, and the position on mayoral referral thresholds for London residential schemes determines when the second look happens.
National policy sits behind all of it. The planning practice guidance chapter on health and wellbeing describes what plans and decisions should take into account, and the current National Planning Policy Framework, published on 17 August 2026, carries the healthy communities policies. Neither imposes an assessment requirement directly.
Check the local plan policy wording, the validation list and any supplementary planning document, in that order, and confirm with the case officer at pre-application stage.
Rapid screening against full assessment
Most schemes need screening, fewer need a rapid assessment, and only a minority need a full one.
| Stage | Typical trigger | Effort |
|---|---|---|
| Screening | Any major development where policy is engaged | A short proforma, often supplied by the council |
| Rapid assessment | Screening identifies effects on one or more determinants | A desk-based matrix with local data and proposed mitigation |
| Full assessment | Large or sensitive schemes, or where screening finds substantial effects | Primary engagement, quantified analysis, a monitoring framework |
The screening proforma is worth taking seriously even though it looks trivial. A screening that records "no effect" against every determinant invites a request for the full assessment, because it reads as though nobody looked. A screening that identifies two or three real effects, explains them and proposes mitigation often closes the question.
Proportionality is the principle the guidance supports, and it cuts both ways. A 60-home scheme in a market town does not need the analysis a 1,200-home urban extension needs, and submitting one anyway wastes the officer's time as well as the client's money.
Determinants of health the assessment covers
The framework used across most English authorities groups effects under a familiar set of headings. In practice the ones that carry weight in a planning decision are these.
- Housing quality and tenure mix, including dwelling size against the nationally described space standard, overheating risk, daylight and the proportion of single aspect units.
- Access to health, education and community facilities, measured by walking time rather than straight-line distance.
- Active travel and public transport, including the quality of the walking route rather than its existence.
- Open space, play provision and access to nature.
- Air quality, noise and light, which usually import conclusions from the technical assessments rather than repeating them.
- Employment, training and local procurement during construction and in the completed development.
- Social cohesion, community safety and the design of shared space.
- The food environment, which in some boroughs brings in restrictions on hot food takeaways near schools.
Write each determinant as a finding, not as a description. An officer wants to know whether the scheme improves, worsens or leaves unchanged the position for the population affected, and on what evidence.
Evidence sources and local health data
The weakness of most submitted assessments is that they cite national averages and stop.
Better sources, all publicly available: the Joint Strategic Needs Assessment for the area, the local authority's own health profile, the Indices of Multiple Deprivation at lower super output area level, and Office for National Statistics population and health data. Ward-level and LSOA-level figures are what make the assessment about this site rather than about England.
Two practical cautions. Do not cherry-pick the indicator that flatters the scheme. And do not state a health outcome as though the development will cause it, because the causal chain between a housing layout and a measured health outcome is long and the assessment will be read by someone who knows that.
Where the Statement of Community Involvement records what residents actually raised, the two documents reinforce each other, because local concerns are evidence of perceived effects even where the data is neutral.
Engagement with public health teams
The public health team sits in the upper-tier authority, which in a two-tier area is the county council rather than the district determining the application. That split catches people out.
Approach them at pre-application stage with a screening output, not with a finished document. A director of public health who has commented on the scope rarely objects to the conclusions later. One who first sees a 90-page report during consultation will find something to object to.
Ask three questions in that meeting: which determinants they consider material for this location, which datasets they expect to see cited, and what mitigation they would regard as proportionate. Record the answers and reflect them in the assessment.
Mitigation and how it is secured
An assessment that identifies effects and proposes nothing is a description. Mitigation has to be capable of being secured.
Design mitigation goes into the drawings and is fixed by the approved plans condition: dual aspect ratios, play space locations, the walking route through the site, the position of the doctor's surgery unit if there is one.
Conditions carry the measurable commitments, for instance a local employment and training scheme, or the provision of allotments before occupation of a stated phase.
Financial contributions are the awkward part. A payment toward health infrastructure has to satisfy the tests in regulation 122 of the Community Infrastructure Levy Regulations 2010: necessary to make the development acceptable in planning terms, directly related to the development, and fairly and reasonably related in scale and kind. A general contribution toward primary care capacity, unsupported by evidence that the scheme creates the need and that the money will be spent on it, fails those tests. Get the evidence from the integrated care board before the obligation is drafted.
A Health Impact Assessment draft can set out the determinants, the local data and a mitigation schedule, and councils usually expect a suitably qualified author, so professional review is strongly advised before submission.
Reporting proportionately to scheme size
Length is not quality. A rapid assessment for a 70-home scheme should run to perhaps fifteen pages: the policy trigger, the population affected, a determinant-by-determinant matrix with findings, a mitigation schedule cross-referenced to the drawings and the draft obligations, and a short monitoring proposal.
A full assessment for a large scheme adds primary engagement, quantified analysis where the data supports it, cumulative effects with other consented development, and a monitoring framework with named indicators and reporting dates.
What belongs in neither: a literature review of the social determinants of health, a restatement of the air quality chapter, or a page of photographs of people walking.
Where the scheme also engages the public sector equality duty under section 149 of the Equality Act 2010, the council prepares its own analysis, and an applicant's Equalities Impact Assessment supports that rather than replacing it.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Enter your postcode on PlanScope to see which reports a major residential scheme is likely to need.
Frequently asked questions
Is a health impact assessment a national requirement?
No. There is no statutory requirement for one in an English planning application. The trigger comes from local plan policy, from the council's local validation list, and in London from the London Plan and borough policies. National planning practice guidance on health and wellbeing describes what should be taken into account without imposing an assessment.
What threshold usually applies?
Most authorities that require one set it at major development, with numerical triggers commonly between 50 and 150 dwellings, and lower triggers in wards with poor health outcomes. Some express it in floorspace instead. Check the policy wording, the validation list and any supplementary planning document, then confirm with the case officer.
What is the difference between a rapid and a full assessment?
A rapid assessment is desk based: a matrix of determinants with local data, findings and proposed mitigation. A full assessment adds primary engagement with affected groups, quantified analysis where data supports it, cumulative effects with other consented schemes, and a monitoring framework with named indicators and reporting dates.
What data should the assessment use?
Local data rather than national averages: the Joint Strategic Needs Assessment, the authority's own health profile, Indices of Multiple Deprivation at lower super output area level, and Office for National Statistics population and health figures. Ward and LSOA level figures are what make the assessment site specific.
Can the council require a contribution to GP capacity?
Only where it satisfies regulation 122 of the Community Infrastructure Levy Regulations 2010: necessary to make the development acceptable, directly related to it, and fairly and reasonably related in scale and kind. Evidence from the integrated care board showing the need arises from the scheme, and how the money will be spent, is what makes such an obligation defensible.
Who in the council reviews the assessment?
The public health team, which sits in the upper-tier authority. In a two-tier area that is the county council rather than the district determining the application. Engage them at pre-application stage with a screening output rather than presenting a finished report during consultation.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.