Lake Elsinore, CA Accessory Structures: ADU Impact Fees (2026)

Lake Elsinore's ADU ordinance ties impact-fee liability directly to unit size. Under LEMC § 17.415.110(E), every ADU and JADU owner must pay sewer, water, and other applicable fees, including the development impact fees authorized by Government Code § 66000 et seq., with one carve-out: an ADU under 750 square feet pays no impact fees at all. Once an ADU reaches 750 square feet or larger, the City charges impact fees proportional to the square footage of the primary dwelling unit on the lot rather than a flat citywide schedule, so the bill scales with how the ADU compares to the house it accompanies.

This size threshold sits on top of the size caps in subsection (D): an attached ADU built alongside an existing home is capped at 50 percent of that home's floor area, and a detached ADU tops out at 1,200 square feet regardless of the primary dwelling's size. Before the Building Official issues a permit, the owner must submit letters confirming water and sewer service availability, and if a private septic system is used, approval from the County Department of Environmental Health is required in place of the sewer letter.

These utility and environmental-health steps apply no matter which fee tier applies. The Community Development Department administers the fee determination as part of building-permit review for the ADU or JADU application under Chapter 17.415 LEMC, and the fee schedule itself is set separately by City Council resolution.