What changes for a scheme of one new dwelling
One new house is not a householder application. Net gain exemptions, the levy start notice and foul drainage evidence are where single plot schemes go wrong.
One new dwelling is a minor full application, not a householder one, and that single classification change brings a different fee basis, a different consultation process and a different document set. The single new dwelling planning requirements that catch self-builders out are the three that did not exist a few years ago or that work differently at this scale: biodiversity net gain, the levy and its self-build relief, and the foul drainage evidence a council now expects up front.
The good news is that a well-prepared single plot application is straightforward. The documents are few, the consultees are few, and the determination period is eight weeks. The bad news is that two of the three items above have hard procedural steps with deadlines, and missing them costs money that cannot be recovered.
Application type, fee and route
A householder application covers alterations or extensions to an existing dwellinghouse. A new dwelling, even one in a back garden, is a minor application for full planning permission, with a determination period of eight weeks and a fee charged per dwelling.
Fees were uplifted in December 2023 and are now indexed annually, so check the current fee schedule rather than relying on a figure from a previous project. The levy and obligations position also varies by authority, as our note on obligations and the levy at different scheme sizes explains.
Two alternative routes exist for a single plot. Outline permission with reserved matters suits a site where the principle is uncertain and you do not want to pay for detailed design yet. Permission in principle, followed by a technical details consent, is available for minor housing-led development and can cost less to test the principle, though fewer authorities are used to processing it. Where the dividing line between householder and minor sits is explained in our note on where the single dwelling line falls.
Biodiversity net gain on one plot
This is the item that surprises people. Mandatory biodiversity net gain applies to small sites as well as major development, and a single new dwelling is not automatically outside it.
Three exemptions matter at this scale. The de minimis exemption applies where the development affects less than 25 m2 of on-site habitat and less than 5 m of linear habitat such as hedgerow. The self-build and custom housebuilding exemption applies to schemes of no more than nine dwellings on a site of no more than 0.5 hectares where the dwellings are built or commissioned by the people who will live in them. And householder applications are outside the regime, which is why an extension is unaffected and a new house is not.
If no exemption applies, the requirement is a 10 per cent gain measured with the statutory metric, secured for 30 years, with a biodiversity gain plan approved by the authority before development begins. A Biodiversity Net Gain Assessment runs that metric, and the Environment Act 2021 regime expects a competent person to complete it, so an AI-assisted draft is a starting point for that person rather than a substitute.
Measure the habitat before you clear the site. A plot stripped of its hedge in advance is assessed on its pre-development condition where the authority can establish it, and clearing to improve the baseline is treated as degradation.
Drainage, water and foul connection
Councils now ask for drainage evidence at validation rather than by condition, and a single plot is no exception.
For foul drainage, connection to the public sewer is the expected solution, and the water and sewerage undertaker's pre-development enquiry confirms capacity and the connection point. Where mains drainage is not available, a package treatment plant or septic tank discharging to ground must comply with the general binding rules, or an environmental permit is needed, and the available discharge route has to be established before the application rather than assumed.
For surface water, the hierarchy starts with infiltration. A soakaway needs an infiltration test to establish whether the ground will take water, and a test carried out in the wrong season or at the wrong depth is the commonest reason a drainage condition fails later. Where infiltration is not viable, a connection to a watercourse needs the consent of the riparian owner or the lead local flood authority, and a connection to a surface water sewer needs the undertaker's agreement.
Where the plot touches a flood zone, a Flood Risk Assessment is required and the sequential approach within the site applies even at this scale.
Ecology and tree triggers
A single plot still triggers protected species work where the site conditions call for it.
Bats are the usual issue, arising where an outbuilding, barn or roof is to be demolished or altered. A protected species survey and any licence require a suitably licensed ecologist under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017, and that is a legal requirement rather than a recommendation. Nesting birds constrain the timing of vegetation clearance through the breeding season. A preliminary ecological appraisal is proportionate where habitats are present on or adjoining the plot.
Trees trigger a BS 5837:2012 survey where any tree within influencing distance of the works is to be retained, and that includes trees on neighbouring land whose root protection areas extend into the plot. Where a tree is protected by an order or sits in a conservation area, the survey is effectively mandatory.
The levy and self-build relief
Where the authority has adopted a community infrastructure levy charging schedule, a new dwelling is chargeable on its net additional floorspace.
Self-build relief removes that charge for a dwelling you will occupy as your sole or main residence, and it has a procedure with teeth.
- Submit the self-build exemption claim before development begins, on the authority's form.
- Receive the authority's acknowledgement granting the exemption.
- Serve the notice the levy regulations require before any work starts on site.
- Within six months of completion, submit the supporting evidence the regulations require, including proof of ownership, occupation and completion.
- Keep the property as your main residence for three years from completion.
Miss that notice and the relief is lost, with the full levy becoming payable and surcharges applying. That is the single most expensive administrative error available to a self-builder, and it happens because groundworkers start while the paperwork is in a drawer.
Access and visibility
A new dwelling means a new or intensified access, and the highway authority will look at visibility splays measured from a set-back point in each direction, judged against the speed of traffic on the road rather than its speed limit.
A new or widened vehicle crossing over the footway needs the highway authority's separate consent under the Highways Act 1980, and works within the highway are carried out under an agreement with the authority rather than by your builder. Refuse collection, turning within the plot so that a vehicle leaves in forward gear on a classified road, and parking that does not rely on reversing into the carriageway all feature in the highways response.
The document set for one plot
For a straightforward infill plot, expect to submit: a location plan at 1:1250 with the site edged red, a block plan showing the proposal in context, existing and proposed floor plans and elevations at a consistent scale, a site plan with levels and the access arrangement, a street scene elevation where the setting is sensitive, the ownership certificate and any notice served, the levy additional information form, the biodiversity position with an exemption claim or a gain plan, drainage details, and any ecology or arboricultural reports the site conditions require.
A short Planning Statement setting out the policy case, the design rationale and how each technical point is answered is not required at this scale but it shortens determination noticeably, because it gives the case officer the report they would otherwise have to write from scratch.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. Enter your postcode on PlanScope to see which reports your plot is likely to need.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Is a new house a householder planning application?
No. Householder applications cover alterations and extensions to an existing dwellinghouse. A new dwelling, including one in a back garden, is a minor application for full planning permission with an eight-week determination period and a fee charged per dwelling. Outline permission or permission in principle are alternative routes for testing the principle.
Does biodiversity net gain apply to a single new dwelling?
Often yes. Small sites are within the regime, so a single house is only outside it if an exemption applies: the de minimis exemption where less than 25 m2 of on-site habitat and less than 5 m of linear habitat are affected, or the self-build and custom housebuilding exemption. Householder applications are outside the regime entirely.
How does the self-build levy exemption work?
Claim it on the authority's form before development begins, obtain the acknowledgement, serve the notice the levy regulations require before any work starts, supply the required evidence within six months of completion, and occupy the dwelling as your sole or main residence for three years. Missing that notice loses the relief and triggers surcharges.
What drainage evidence does a council want for one plot?
A pre-development enquiry response from the water and sewerage undertaker confirming the foul connection point and capacity, or the general binding rules position for a package treatment plant. For surface water, an infiltration test for a soakaway, or evidence of agreement for a watercourse or surface water sewer connection.
Do I need a tree survey for a single plot?
Where any tree within influencing distance of the works is to be retained, including trees on neighbouring land whose root protection areas reach into the plot. A BS 5837:2012 survey is effectively mandatory where a tree is covered by a preservation order or stands within a conservation area.
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.