Cumberland County, ME Accessory Structures: ADU Impact Fees (2026)

Cumberland County does not levy impact fees. There is no county building permit, no county school district (Maine schools are organized at the municipal/RSU level), no county water/sewer utility, and no county capital improvement plan that would support an impact fee. Impact-fee authority in Maine flows entirely through 30-A MRS § 4354 to MUNICIPALITIES. That statute requires (1) a written capital improvement plan, (2) a rational nexus between the new development and the impact on the public facility, (3) proportionality between the fee and the development's share of capacity, and (4) earmarked accounts spent only on the planned improvements. LD 2003 (the state ADU mandate at 30-A MRS § 4364-B) does not expressly cap ADU impact fees, but the Maine DECD's LD 2003 guidance treats prohibitive fees as a potential preemption violation if they effectively deter the ADU the statute requires the town to allow. Most Cumberland County municipalities (e.g., Scarborough, Gorham, Cumberland) maintain impact fees for schools, transportation, fire, or recreation; the fee schedule applies to each new dwelling unit including ADUs but is collected at the municipal level only. Sewer and water connection fees are collected by the relevant utility — the Portland Water District, Brunswick Sewer District, etc. — not the county.