Five of the technical reports that UK planning applications rely on changed in 2026 — and the planning report rule changes in 2026 are not evenly spread. Flood risk and biodiversity net gain changed this year, in force now; energy changed on paper in March but does not bite until March 2027; air quality has shifted in emphasis rather than in law; and daylight has not changed at all yet, though a new standard is expected before the year is out.
This guide sets out what actually changed for each of the five reports, the exact dates, and what it means for an application you are preparing today (10 August 2026). It is a companion to our overview of which planning application reports you need — that page tells you whether you need a report; this one tells you what has moved.
Planning report rule changes in 2026 at a glance
| Report | What changed | Date | In force? |
|---|---|---|---|
| Daylight & sunlight | BRE/RICS 2nd edition daylight standard in development | Expected around end of 2026 | No — BR 209 (2022) still applies |
| Flood risk | Flood Map for Planning gains surface water extents and banded depths, present day and climate change | 28 May 2026 | Yes |
| Air quality | Emphasis on population exposure to PM2.5; EPUK/IAQM planning guidance being rewritten | Exposure draft consultation expected Q3 2026 | Partly — Defra interim planning guidance already applies |
| Energy | Future Homes Standard (Part L 2026) Approved Documents published | Published 24 March 2026 | No — in force 24 March 2027 |
| Sustainability | New 0.2 ha biodiversity net gain exemption; self-build exemption removed | 6 August 2026 | Yes |
Two of those five — flood risk and sustainability — change what you submit today. The other three change what you should be planning for.
Daylight and sunlight: nothing has changed yet, and that matters
The most common misconception we hear in 2026 is that the daylight rules have already moved. They have not. BRE BR 209 in its 2022 third edition remains the document local planning authorities assess schemes against, and the RICS Daylighting and sunlighting professional standard, reissued in October 2023, sits alongside it.
What is coming is a joint BRE and RICS second-edition daylight standard, which RICS says is expected around the end of 2026. Until it lands and until councils adopt it, the assessment you commission today is still built on the familiar tests: vertical sky component, no-sky line and annual probable sunlight hours, with BS EN 17037 target illuminance for internal daylight provision. Our table of BRE 2022 daylight targets sets out the numbers in one place, and we track the forthcoming standard in what the second edition means.
The practical consequence
If a consultant tells you your scheme needs re-modelling because "the daylight rules changed in 2026", ask which document they mean. There is no new daylight standard in force. The genuine 2026 pressure on daylight comes from elsewhere — density. Higher-density housing policy pushes schemes towards tighter separation distances and deeper plans, which is where BRE shortfalls appear. We covered that in what higher-density planning means for daylight.
Flood risk: the 28 May 2026 Flood Map for Planning update
This is the change with the most immediate effect on live applications. On 28 May 2026 the Environment Agency added surface water data to the Flood Map for Planning, and the standing advice on gov.uk was updated the same day.
Two things arrived together:
- Surface water spatial planning extents — present day and climate change — showing where surface water flooding is expected at the 3.3% (1 in 30), 1% (1 in 100) and 0.1% (1 in 1,000) annual exceedance probability events.
- Banded depth information for the same scenarios, split across seven bands running from under 150 mm to over 2,300 mm.
Depth is the genuinely new capability. Before this update, a surface water map told you water was expected to flow across a site but not how deep it would sit. Depth bands let an assessment argue proportionately: 100 mm of ponding across a driveway is a different planning question from 900 mm against a habitable floor, and finished floor levels can now be set against published data rather than inference.
The climate change layer also changed character. It uses an upper-end projection for the 2070s epoch, replacing the practice of borrowing the central 2050s scenario from the Check Your Long Term Flood Risk service. That service should now come out of your planning workflow entirely for surface water.
What this means for an FRA you are writing now
Three consequences follow, and they are not theoretical:
- Some sites moved. A site screened as low surface water risk before 28 May 2026 may screen differently now. If your assessment predates the update, re-run the screening before you submit.
- Reviewers will expect depths. An FRA that cites extents but ignores the published depth bands looks dated to a lead local flood authority.
- Drainage sits inside the design, not after it. That direction of travel is reinforced by the SuDS national standards work — see SuDS and your FRA in 2026.
We go deeper on both parts in the 2026 Flood Map for Planning update and using the new flood depth bands. If you only want to know your zone, our free flood zone checker gives you it from a postcode.
Air quality: the shift from compliance to exposure
Air quality has no single 2026 commencement date, which is exactly why it catches applicants out. The change is one of emphasis, and it has been building since Defra published its PM2.5 Targets: Interim Planning Guidance on 4 October 2024.
The Environment Act targets that guidance serves are a maximum annual mean PM2.5 concentration of 10 µg/m³ and a 35% reduction in population exposure against a 2018 baseline, both by 2040. The planning consequence is that demonstrating your scheme sits below the statutory objectives is no longer the whole answer. Applicants are asked to show they considered exposure when choosing and laying out the site, and that they have minimised PM2.5 emissions as far as is reasonably practicable — with the evidence written into the air quality assessment.
Running alongside this, EPUK and the Institute of Air Quality Management are rewriting Land-Use Planning & Development Control: Planning for Air Quality. It is a substantive update, with member consultation on the exposure draft expected in the third quarter of 2026 and potentially more than one round. The current guidance still governs assessments submitted today, as does the IAQM dust guidance (v2.2, January 2024) and Defra LAQM.TG(22).
What a 2026-standard air quality assessment looks like
In practice, the reports that survive scrutiny now do three things a 2022-vintage report often did not: they place new receptors deliberately rather than incidentally, they address PM2.5 exposure separately from NO₂ compliance, and they carry mitigation that is specific enough to be conditioned. We unpack the direction of travel in population exposure, not just compliance and the numbers in PM2.5 and the Environment Act targets. To check whether your site sits inside a declared area, use the free AQMA checker.
Energy: Part L 2026 is published but not yet in force
On 24 March 2026 MHCLG published the Future Homes Standard — the 2026 revision of Approved Document L for England. The headline is a minimum 75% cut in regulated carbon emissions against the 2013 standard, and a new functional requirement obliging on-site renewable electricity generation on new dwellings — in practice rooftop solar PV sized against the dwelling's ground-floor area, with a documented "reasonable amount" allowed where shading, orientation or roof geometry make the full figure impractical.
The date that matters for anyone writing an energy statement this month is the one that has not arrived. The new requirements come into force on 24 March 2027, with transitional arrangements for schemes already under way and staged application by building type. Until then, Part L 2021 and the SAP 10.2 notional-building method remain the baseline your energy statement is measured against, and SAP 10.3 will be the approved compliance methodology when the standard goes live, with the Home Energy Model following afterwards during a dual-running period.
For London schemes, none of this displaces London Plan Policy SI2 — the 35% on-site carbon reduction target and carbon offset contributions still apply and are assessed against the current Part L baseline.
The design decision the 2027 date forces
If your scheme will be built after March 2027 but is submitted for planning now, you have a choice: design to Part L 2021 and accept a redesign at building control stage, or design to the Future Homes Standard now and present a stronger energy statement in the meantime. Heat pumps and a properly sized solar array are the two decisions that determine which side of that line you land on. See which standard applies to your project, sizing solar PV and SAP 10.3 and the Home Energy Model.
Sustainability: the 6 August 2026 biodiversity net gain changes
Four days before this article was published, the biodiversity net gain regime changed for small sites in England. From 6 August 2026:
- A new small-site exemption applies. Mandatory BNG generally does not apply where the development site is 0.2 hectares (2,000 m²) or smaller — measured on the red-line planning boundary, not on the area of habitat being removed.
- The exemption has a hard condition. It does not apply where the development affects on-site priority habitat. A small site with priority habitat is still in scope.
- The self-build and custom-build exemption is gone. It no longer applies to planning applications made on or after 6 August 2026 — so a self-build over 0.2 ha that would previously have been exempt now needs BNG.
- Temporary development rules were adjusted, alongside transitional arrangements published by Defra on 14 July 2026.
Read the gov.uk biodiversity net gain guidance for the statutory position. Our own coverage is split across the new 0.2 hectare exemption, the end of the self-build exemption and the 2026 changes in full. A separate date is worth diarising: BNG becomes mandatory for nationally significant infrastructure projects from 2 November 2026.
Everything else in a sustainability statement is unchanged. The 110 litres per person per day water efficiency standard still applies under Part G, the London Plan Urban Greening Factor still applies to London sites under Policy G5, and BREEAM is still required where a local policy or condition asks for it.
What has not landed yet: the revised NPPF
The largest pending change sits above all five reports. A draft revised National Planning Policy Framework was published on 16 December 2025, with consultation closing on 10 March 2026, and the Government has said the final version is expected in summer 2026. At the time of writing it has not been published.
The draft restructures national policy, introduces national decision-making policies to sit alongside local plans, and proposes a strong presumption in favour of higher-density residential development near well-connected stations. Every one of the five reports feels that: denser schemes are harder daylight cases, carry more impermeable area, put more receptors near roads and place more pressure on on-site biodiversity. Watch for it, but do not write it into a submission before it exists.
What to do before you submit
- Check the date on your flood data. Anything screened before 28 May 2026 needs re-checking against the new surface water extents and depth bands.
- Confirm your BNG position against the 6 August 2026 rules — site area, priority habitat, and whether you were relying on the now-withdrawn self-build exemption.
- State the Part L version explicitly in your energy statement, and say why. Assessors should not have to guess whether you modelled 2021 or 2026.
- Address PM2.5 exposure in the air quality assessment, not only compliance with the objectives.
- Do not rewrite daylight work in anticipation of a standard that has not been issued.
- Re-read the council's validation list. Local requirements change independently of national ones, and a missing document is still the most common reason an application is invalidated.
Frequently asked questions
Did the daylight rules change in 2026?
No. BRE BR 209 (2022) and the RICS professional standard reissued in October 2023 remain current. A joint BRE/RICS second edition is expected around the end of 2026, and councils will then need time to adopt it.
Do I need a new flood risk assessment if mine was written before 28 May 2026?
Not automatically, but the surface water screening in it should be re-run. If the new extents or depth bands change the picture for your site, the assessment needs updating before submission — a reviewer will check the same source you did.
Should my energy statement use Part L 2021 or the Future Homes Standard?
Part L 2021 remains the compliance baseline until 24 March 2027. Modelling to the Future Homes Standard early is a design choice, not a requirement — it can strengthen a planning case, particularly where a policy target such as London Plan SI2 applies.
Is my small site now exempt from biodiversity net gain?
Possibly. If the red-line site area is 0.2 hectares or less and no on-site priority habitat is affected, mandatory BNG generally does not apply to applications made on or after 6 August 2026. Priority habitat on site removes the exemption.
Do these changes apply across the whole UK?
No. The flood map update, the BNG regime and Approved Document L are England measures. Scotland, Wales and Northern Ireland run their own frameworks — NPF4, Planning Policy Wales and the SPPS respectively — and flood and biodiversity policy differ accordingly. Air quality guidance from IAQM and Defra applies more broadly.
How much do these reports cost?
It varies with site complexity and scheme size rather than with the rule changes themselves. We set out indicative ranges in our guide to planning report costs.
Key takeaways
- Two changes are live now: the 28 May 2026 Flood Map for Planning update and the 6 August 2026 BNG changes. Both affect what you submit today.
- One is published but deferred: Part L 2026 / the Future Homes Standard, in force 24 March 2027. Part L 2021 and SAP 10.2 remain the baseline until then.
- One is a change of emphasis: air quality assessments are expected to address PM2.5 population exposure, with the EPUK/IAQM planning guidance being rewritten during 2026.
- One has not happened: there is no new daylight standard in force. BR 209 (2022) still governs.
- The revised NPPF is still pending and, when it lands, will affect all five reports through density.
- Dates beat opinions. Every claim in a report that cites a standard should cite its version and date — that alone removes a large share of reviewer queries.
How Fortress Associates can help
We produce all five reports, and each one is written against the version of the guidance that applies on the day you submit. Our daylight and sunlight reports are prepared to BRE BR 209 (2022) and BS EN 17037, typically delivered in four to five working days with no advance payment.
The other four are automated and site-specific, produced free and ready in minutes. The flood risk assessment pulls live Environment Agency data and follows the EA FRA template (March 2025), with a SuDS drainage strategy to CIRIA C753. The air quality assessment uses live Defra background maps, national AQMA boundaries and DfT traffic counts, following IAQM, EPUK/IAQM and LAQM.TG(22) guidance. The energy statement builds a Part L 2021 baseline on the SAP 10.2 notional-building method and works through the full Be Lean, Be Clean, Be Green hierarchy. The sustainability statement covers energy, the 110 l/p/d water calculator, 10% biodiversity net gain, urban greening and BREEAM where required. All four cover every UK local authority.
You can also run the screening yourself first — our free planning tools include flood zone, AQMA, BNG exemption and carbon offset checkers. To discuss a specific site, see our services or get in touch.
Sources & further reading
- Flood map for planning — GOV.UK
- Flood risk assessment: standing advice — GOV.UK (updated 28 May 2026)
- PM2.5 targets: interim planning guidance — Defra UK-AIR
- IAQM guidance library
- Approved Document L: conservation of fuel and power — GOV.UK
- Understanding biodiversity net gain — GOV.UK
- National Planning Policy Framework — GOV.UK
- Daylighting and sunlighting — RICS professional standard
- BRE BR 209 (2022) — Site layout planning for daylight and sunlight
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