Key Facts Ordinance Text Full Breakdown Violations FAQ Sources More in Meridian

Meridian, ID Accessory Structures: ADU Rules (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Meridian, ID, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Max size: 900 sq ft or 50% of primary home
Units per lot: One ADU maximum
Permit: City permit required before building
Utilities: Must connect to city water/sewer
Address: Separate address required

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in Idaho under recent ADU streamlining laws. The Meridian, ID rules below cover local size, height, and setback requirements.

Summary

Meridian caps accessory dwelling units at 900 square feet or half the primary home, requires a city permit, and limits every property to just one ADU.

E. Maximum size. An accessory dwelling units shall be limited to a maximum of nine hundred (900) square feet or no more than fifty (50) percent of the primary dwelling, whichever is less, and no more than two (2) bedrooms constructed in accord with the adopted residential building code. ... G. Parking. ... The conversion of a covered parking area (garage/carport) into an accessory dwelling unit is not allowed unless the required parking can be provided elsewhere on site.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14).

Full Breakdown

Meridian City Code § 11-4-3-12 sets citywide ADU standards: one accessory dwelling unit per property, subordinate to and on the same lot as the primary dwelling, and a city permit is required before building, placing, or maintaining one. Size is capped at 900 square feet or 50% of the primary dwelling's size, whichever is smaller, with no more than two bedrooms. The unit must connect to city water and sewer, get its own address, and cannot be a converted garage unless replacement parking is provided elsewhere on the lot.

Violations & Fines

Building or maintaining an ADU without the required city permit, exceeding the 900-sq-ft/50% size cap, or converting required garage parking without replacing it are code violations enforceable by the City of Meridian.

Frequently Asked Questions

Can I turn my garage into an ADU in Meridian?

Only if you replace the required parking elsewhere on the property; converting covered parking into an ADU without doing so is not allowed under § 11-4-3-12(G).

How big can a Meridian ADU be?

Up to 900 square feet or 50% of the primary dwelling's size, whichever is less, with a maximum of two bedrooms.

Sources & Official References

[1]Meridian City Code § 11-4-3-12

Other rules in Meridian

Noise Ordinances: Quiet HoursSome Restrictions Shed & Carport RulesSome Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Decibel LimitsSome Restrictions Parking Rules: Driveway RulesSome Restrictions Parking Rules: Loading ZonesSome Restrictions Animal Ordinances: Breed RestrictionsSignificant Restrictions

All Meridian rules

How Meridian compares: Easiest Cities to Build an ADU·Compare Meridian to another location·View the Idaho accessory structures overview

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.

ADU Rules in Nearby Cities

How other cities in this county handle adu rules.

Boise, ID