Turning a garage into an ADU in Folsom

Short answer

Folsom's code includes an ADU in existing space among the units on a single-family lot and waives replacement parking when a garage is removed for one. State law also protects parking lost to a conversion and the existing structure's setback.

Last verified 2026-10-18. Rules change; the City of Folsom planning desk has the final word (916-461-6202).

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What the Folsom rules allow on your lot: setbacks, the biggest unit that fits, fees.

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The rules

ADUs per single-family lotLocal rule: Up to 3 ADUs (one of each type) + 1 junior ADUFolsom Municipal Code 17.105.120(A)(1)
Parking for a City-rules ADULocal rule: At most 1 space, with exceptions; no replacement parkingFolsom Municipal Code 17.105.180
SewerLocal rule: Public sewer; septic only where the City allows itFolsom Municipal Code 17.105.130(B) and (C)
Planning deskLocal rule: PlanningEPC@folsom.ca.us, 916-461-6202City of Folsom Planning Division, ADU page
Setback for an existing-space conversionState law: No new setback for an existing structure, or one rebuilt in the same place and dimensions, converted to an ADUGov. Code 66314(d)(7)
Replacement parking for a converted garageState law: No replacement parking required for spaces removed or converted for an ADUGov. Code 66314(d)(11)
Detached-garage demolition permitState law: If a detached garage is replaced with an ADU, its demolition permit is reviewed with the ADU application and issued at the same timeGov. Code 66314(e)
Entry and exit expansion for an existing-space ADUState law: On a single-family lot, an existing accessory structure may expand by up to 150 sq ft beyond its dimensions, only to accommodate entry and exitGov. Code 66323(a)(1)(A)

What to know in Folsom

Folsom parking and utility rules for a conversion

Folsom Municipal Code 17.105.180 says garage parking removed for an ADU does not have to be replaced. Section 17.105.130 requires ADUs to connect to public utilities or their equivalent, including water, electric and sewer service; an on-site treatment system needs City permission.

Folsom Municipal Code 17.105.130(B)-(C) and 17.105.180(C)

Estimated cost and rent

Garage conversions and junior ADUs aren't in this table for Folsom: the check can't verify them there yet, so a report lists them as not verified.

What we couldn't confirm

We could not confirm whether a particular Folsom garage meets conversion building requirements or the City's permit and plan-check dollar total.

Ask the City of Folsom planning desk before you rely on these.

Check your lot free

Our free check reads your lot against the Folsom rules above from public records: a screening, not a permit or professional advice.

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Floor plans to start from

Measured ADU layouts you can edit and download as CAD files, then check against the Folsom rules above.

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We'll match you with a licensed designer and builder in your area and coordinate the project. Free consult, no obligation.

Licensed partner designers and builders do the design and construction, and the builder holds the construction contract. Partners are signed in some areas so far; elsewhere we'll tell you plainly what we can do.

Folsom garage conversion questions

Must I replace garage parking for a Folsom ADU?

No. Folsom Municipal Code 17.105.180(C) waives replacement parking when a garage or carport space is removed for an ADU. Government Code section 66314(d)(11) also covers a garage converted to an ADU.

Can an existing Folsom garage keep its setback?

Government Code section 66314(d)(7) says a converted existing accessory structure does not need a new setback. On a single-family lot, section 66323(a)(1)(A) limits an expansion beyond the existing structure to entry and exit space.

What utility service does a converted Folsom garage need?

Folsom Municipal Code 17.105.130(B)-(C) requires ADUs to connect to public utilities or their equivalent, including water, electric and sewer. An on-site water-treatment system is allowed only when the City allows it under Chapter 13.20.

Is this a permit, or a plan I can build from?

Neither. It is a screening from public records, not professional advice, and not a survey, soils report, appraisal, loan offer or permit; every number is an estimate. A licensed designer confirms the final plan, and your city or county gives final approval.