Merced Zoning and ADU Guide for Homeowners and Sellers

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team. Information comes from the City of Merced’s Homeowner’s How-To Guide to Accessory Dwelling Units and its Building Division pages; sources are listed at the end.

In the City of Merced, an accessory dwelling unit (ADU) does not need a separate planning permit: you apply for a building permit with the Inspection Services Division, and the city’s guide says a complete application on a lot with an existing home is acted on within 60 days or deemed approved. The city also runs a pre-approved ADU program with free plan sets.

For a seller, the question is usually the reverse: what do you do about a garage conversion or backyard unit that was built without any of this? This guide covers the city’s published standards and how an unpermitted unit affects a sale.

Merced ADU rules at a glance

Where ADUs are allowed in Merced

The city says ADUs are permitted on parcels zoned residential or allowing residential use, including single-family, multifamily and mixed-use, that have an existing or proposed home and are connected to public water and sewer service.

You can check your zoning on the city’s zoning map and confirm eligibility with the Planning Division.

Minimum rules apply regardless of lot size: the city’s guide says an ADU of up to 800 square feet is always allowed if it stays under 16 feet tall, keeps 4-foot side and rear setbacks and meets fire and building codes.

Types of ADU

• Attached ADU: shares at least one wall with the main home.
• Detached ADU: a freestanding structure.
• Converted ADU: interior space such as an attic or garage turned into a unit.
• Junior ADU (JADU): contained entirely within the home and no more than 500 square feet.

Parking, occupancy and rental rules

Merced requires at most one additional off-street space per ADU or per bedroom, whichever is less, and it can be tandem in the driveway. No replacement parking is required when a garage is converted. Exceptions apply near transit, in historic districts, for attached or converted units and near car-share vehicles.

Rentals must be at least 30 continuous days; short-term rentals are not allowed. After January 1, 2025, a new ADU in an R-1 zone requires the owner to live in either the main home or the ADU and rent only one of them.

A JADU requires owner occupancy and a deed restriction before the building permit is issued. An ADU cannot be sold separately from the main home, except by a qualified nonprofit under Government Code section 65852.26.

Fees

The city’s guide says ADUs under 500 square feet pay no city impact fees or school fees. Units between 500 and 750 square feet pay school district fees only, charged proportionately. Units over 750 square feet pay both.

Units created inside an existing home or accessory structure are not charged new sewer or water connection fees, though water lines may need upgrading to current standards at the owner’s expense. Impact fees are due before final inspection.

The pre-approved ADU program

The city offers three pre-reviewed detached ADU plan sets at no cost, at 498, 749 and 1,190 square feet, each with a choice of design styles. The plans already meet the city’s height, size, foundation and architecture standards.

The owner still supplies the building permit application, site plan, roof framing plan, truss calculations, permit fees and any required impact fees, and the program does not include separate submittals for trusses, solar or fire sprinklers.

The 749-square-foot plan has one bedroom, a flex room that can become a second bedroom, a living area, kitchen, laundry closet and bathroom.

What a permit application needs

Applications are submitted electronically to Inspection Services. The city’s checklist calls for a site plan, floor plan, four elevations, foundation plan, a soils moisture and compaction report, roof framing plan, electrical and mechanical plans, a Title 24 energy analysis, detail sheets, a shear wall plan and fees.

Fire sprinklers are required for an ADU if they are required for the main home, and a new detached ADU generally needs solar panels under the state energy code, with exceptions. If you demolish an existing structure, a demolition permit is also required.

State law behind the city rules

Merced’s ordinance follows California’s ADU statutes, now codified at Government Code sections 66310 through 66342. State law also protects a four-foot side and rear setback for a new ADU, and allows conversion of existing space without added setbacks. A city cannot require replacement parking when a garage is converted.

These rules matter for sellers because a unit that would have been approved today may still be treated as unpermitted if it was built without a permit.

How an unpermitted unit affects selling a Merced house

An unpermitted garage conversion, backyard cottage or room addition is a common reason Merced listings stall. Lenders and appraisers generally count only permitted living space, so the unit may add nothing to appraised value and can trigger repair or legalization requests. California sellers must disclose known unpermitted work.

Read our guides on selling as-is with unpermitted work and seller disclosures. If the city has already sent a notice, see our Merced code enforcement guide.

Your options for an unpermitted unit

1. Legalize it. Talk to Inspection Services about what the city would require, and get a contractor’s estimate, which may include opening walls, utility work and fees.
2. Remove it. Return the space to its permitted use, such as a garage.
3. Sell with a repair credit. Price the house to reflect the work and let a buyer decide.
4. Sell as-is for cash. A cash buyer purchases the property in its current condition, without a lender’s appraisal or inspection contingency.

We buy Merced houses as they are, including those with converted garages and unpermitted units. See how our Merced cash-offer process works.

Not sure whether your unit was permitted? Call (424) 435-2326 or request a cash offer. There is no cost and no obligation.

Merced zoning and ADU FAQ

Do I need a planning permit for an ADU in Merced?

No. The city says there are no special planning permits for ADUs; you apply for a building permit with Inspection Services.

How big can a Merced ADU be?

A detached ADU can be up to 1,200 square feet. An attached or converted ADU is limited to 50 percent of the home’s living area or 1,200 square feet, whichever is less, and a junior ADU is limited to 500 square feet.

Can I sell my ADU separately from the house?

No. An ADU cannot be sold separately from the main home except by a qualified nonprofit corporation to a qualified buyer.

Can I sell a Merced house with an unpermitted unit?

Yes. It must be disclosed, but a cash buyer can purchase the property as-is without requiring you to legalize the unit first.

Sources

• City of Merced: A Homeowner’s How-To Guide to Accessory Dwelling Units
• City of Merced: Pre-Approved ADU Program
• City of Merced: 749 sq ft pre-approved plan

This guide is general information, not legal advice. ADU rules change; confirm requirements with the City of Merced Planning and Inspection Services divisions.