Guide Unilateral undertakings, section 106 agreements, habitat mitigation and affordable housing contributions

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1. What are planning obligations, and how much will it cost?

Planning obligations

Planning obligations are legal documents that require developers to undertake certain works or make financial contributions in order to mitigate the impacts of the development proposed. Planning obligations are most commonly used on residential developments where the proposed new dwellings will lead to additional demands on affordable housing, habitats and other local infrastructure. All new developments must address the likely obligations relevant to the scale of development proposed. Most commonly, these obligations are met through a Unilateral Undertaking or S.111 Agreement. However, for more complex applications, a Section 106 (S106) agreement is required.

Unilateral undertakings - How much will it cost?

Affordable housing

The thresholds (number of homes on a scheme) where affordable housing can be required are established in a combination of National Planning Guidance and Local Planning Policy and vary by location. Our adopted Local Plan policy on affordable housing requires contributions to be sought from all sites, unless Government Guidance indicates otherwise.

Following publication of the new NPPF in 2018, the Council’s position with regard to securing affordable housing obligations has changed slightly. Prior to the new NPPF the Council was governed by the NPPG that states that tariff contributions should not be sought from developments of 10-units or less, and which have a maximum combined gross floorspace of no more than 1000sqm. However in designated rural areas, local planning authorities may choose to apply a lower threshold of 5-units. The Council choose to apply the lower threshold.

However, the new NPPF introduces an affordable housing threshold of 10 units or more (or 0.5 hectares or more).

For East Devon, this means that the local authority will seek on-site provision of affordable housing for developments of 10 additional residential dwellings or more in the Wards of Exmouth, Sidmouth, Honiton and Seaton.

In the designated rural areas (all land outside of the wards of Exmouth, Sidmouth, Honiton and Seaton) the local planning authority will seek a financial contribution from developments of between 6-9 units.

The provision of on-site affordable housing will need to be secured through a negotiated Section 106 agreement. Applications where this applies should be accompanied by Heads of Terms outline the affordable housing offer and how this complies with planning policy. For applications where it is not viable to provide the required affordable housing on-site, the Heads of Terms should detail the reasons why and be accompanied by a Viability Appraisal demonstrating that on-site provision at the policy required level is not viable.

For applications where a financial contribution is being provided, a Unilateral Undertaking should be provided with the application securing payment of the contribution.

If you are able to claim Vacant Building Credit against existing building, the proportionate amount can be deducted from the financial contribution payable.

For information on how much the affordable housing contribution will be, and whether you are able to apply Vacant Building Credit, please contact the planning department who will endeavour to provide you with the relevant figure within 10 working days of receipt of the necessary information.

Open space

Historically we have required applicants to submit a unilateral undertaking for off-site open space provision to meet the needs for open space arising from the proposed development. However, such contributions are now covered by the Community Infrastructure Levy (CIL). A Section 106 Agreement will be required to secure on-site open space/play space provision.

Habitat mitigation

Despite the introduction of the Community Infrastructure Levy (CIL) where a proportion of CIL goes towards infrastructure to mitigate any impact upon habitats, contributions towards non-infrastructure mitigation are also required as development that will impact on a protected habitat cannot proceed under an EU directive unless fully mitigated. Evidence shows that all new dwellings within 10 kilometres of the Exe Estuary and/or the Pebblebed Heaths Special Protection Areas (SPA's) will have a significant effect on protected habitats and hence a mitigation contribution towards non-infrastructure is required for all new dwellings from the 1st May 2017.

The charges for non-infrastructure are formulated as follows:  


Total Charge Per New Dwelling for applications received prior to the 1st April 2021

Total Charge Per New Dwelling for applications received from the 1st April 2021

Exe Estuary Only



Pebblebed Heaths Only



Exe Estuary and Pebblebed Heaths



View our map to see whether your site lies within 10 kilometres of the SPA boundaries.

What do I need to send in?

If your application includes additional residential units you will need to submit a Unilateral Undertaking to secure the affordable housing contribution.

The Unilateral Undertaking template is available for completion here:

Alternatively the contribution can be secured via a S.106 Agreement and your application will need to be accompanied by Heads of Terms outlining the contribution being offered.

If you application includes additional residential units and falls within 10 kilometres of the SPA boundaries, you will need to submit a S.111 Form (along with the appropriate contribution)– further information and templates are available.

When you submit a Unilateral Undertaking, you will have to make sure you have included all the relevant documentation. You will need to return the following documents:

  • One original, signed unilateral undertaking;
  • A cheque for £50, made payable to East Devon District Council, to cover registration costs.

If you decide to submit a S.111 Form with up-front payment, you will have to make sure you have included all the relevant documentation. You will need to return the following documents:

  • One original, completed and signed S.111 Form;
  • A cheque (made payable to East Devon District Council) for the relevant contribution amount unless payment is to be made over the telephone.

Please note that we will require a completed Unilateral Undertaking and/or S.111 Form and payment securing any necessary Affordable Housing and/or Habitat contribution in order to validate and start considering an application.