Somerset Council lists residential-annexe relief from the Community Infrastructure Levy (CIL), but a published relief route does not establish that a particular project qualifies or that a CIL charge applies to its site. The council’s page says the claimant must own and occupy the main dwelling as their sole or main residence and keep the annexe ancillary to it.
Check the national conditions
England’s CIL guidance describes an annexe exemption where the annexe is within the grounds, or curtilage, of the principal home and creates one new dwelling. The person claiming must have a material interest in the main dwelling and use it as their principal residence. A local label such as “ADU” or “granny annexe” does not decide whether a proposed unit meets this test.
The exemption has a separate three-year condition. Under the national guidance, it can be withdrawn if the main house is used for a purpose other than as a single dwelling, the annexe is let, or either the main residence or annexe is sold separately from the other within three years of completion. For this exemption, the guidance defines completion by the issue of the annexe’s compliance certificate. Check the current CIL regulations and ask the collecting authority how the rule applies to the project’s permission and circumstances.
Confirm every notice before work starts
The Somerset page says it must receive a valid Assumption of Liability Notice (Form 2) and Commencement Notice (Form 6) before work starts for the listed relief route, with a stated exception for section 73 applications. England’s GOV.UK guidance separately identifies Form 8 as the residential-annexe exemption claim and says a Form 6 notice is required before site work. Confirm the current local checklist and make sure the authority has received every applicable claim and notice before development commences.
The two official pages describe late-notice consequences differently. Somerset’s page says the relief becomes void if the required notices are not received before work starts, subject to its stated section 73 exception. The national guidance says a late Commencement Notice after an exemption has been granted can trigger a surcharge, and explains that the applicable consequence can depend on when the Liability Notice was issued. Somerset’s page was last updated on February 2, 2026 and shows a next review due date of August 2, 2026. Because that review date has passed, ask Somerset Council to confirm the current rule and required sequence before work begins.
The GOV.UK page records an overall update on June 17, 2026, while its residential-annexe paragraphs show a revision date of September 1, 2019. The current page therefore does not by itself resolve how the local wording and notice history apply to an individual project.
What the local page cannot determine
Somerset Council’s relief page does not give a parcel-specific CIL amount or decide whether a proposed unit is legally an annexe. CIL only applies where a charging schedule covers the development, and the authority must assess the project’s facts. Ask the Council to confirm the charging area, current schedule, classification, required documents, and relief decision. Relief from CIL does not establish planning permission, building-regulations compliance, utility capacity, fire safety, or permission to occupy.