How United Build Partners helps Murrieta homeowners
We're not a construction company. United Build Partners is an ADU advisory and contractor-matching service: we start with a free review of your property and goals, help you understand what's realistic for your lot under Murrieta's rules, and — when it's a good fit — connect you with up to three contractors in our network suited to your project type and neighborhood. From there, you compare proposals and decide who to work with; the licensed contractor you choose handles the actual design and construction.
ADU rules and permitting in Murrieta
Every ADU in California starts from the same statewide floor: ministerial (by-right) approval, at least 16 feet of height, 4-foot side and rear setbacks, and size minimums the city can't undercut. Murrieta adopts the state framework and adds a few specifics worth knowing — especially on fees. Here's what stands out.
What's specific to Murrieta
- Impact fees scale with your home's size — above 750 sq ft. Murrieta charges no impact fees on an ADU under 750 square feet. Above that, fees are charged proportionately to your primary home's size: the city's own example is a 1,000 sq ft ADU on a 2,000 sq ft house billed on a 50% basis. It's an unusually transparent formula — and a real reason to weigh staying at or under 750 sq ft.
- Detached ADUs cap at 1,200 sq ft; attached at 50% of the house. A detached ADU may not exceed 1,200 square feet; an attached ADU is limited to 50% of the main home's floor area; and a JADU is capped at 500 square feet. California's size floors (850 sq ft studio/1-bed, 1,000 sq ft 2+ bed) still apply as a guarantee.
- Pre-Approved ADU Program. Murrieta runs a Pre-Approved ADU Program (Information Bulletin IB-113) to speed permitting, with plans developed by architects, engineers, and draftspersons. Where a pre-approved plan fits your lot, it can shorten design and review — see our pre-approved plans guide.
- By-right building permit — no discretionary review. A qualifying ADU is allowed “by-right” with a building permit only, provided your lot has an existing (or concurrently built) main residence. That keeps approval ministerial rather than discretionary.
- Rentals must be longer than 30 days. Both ADUs and JADUs may be rented, but only for terms longer than 30 days — so long-term tenancy is fine and short-term or vacation rental is not.
- Standard 4-foot setbacks; conversions keep theirs. New ADU construction uses 4-foot rear and side setbacks; a conversion of an existing structure can keep its existing setbacks, and a JADU needs no separate water, sewer, or power connection. Standards are in Municipal Code §16.44.160.
Property and lot considerations
Murrieta is a master-planned Riverside County city next to Temecula, with many tract neighborhoods and active HOAs. The proportional impact-fee formula makes your primary home's size directly relevant to the budget, which is unusual and worth modeling early. An HOA can't override state ADU law (see our HOA guide), but design standards can still apply. A free property review is the fastest way to see what your specific parcel will support; our size & setback calculator is a good first check.
Common ADU types for Murrieta homeowners
Detached ADUs (up to 1,200 sq ft), attached ADUs (up to 50% of the home), junior ADUs (up to 500 sq ft), multi-family options, and pre-approved plans are all available in Murrieta. Because rentals must be long-term, the practical question is which layout best serves a tenant or family member — our which-ADU quiz helps narrow it to your lot and goals.
Cost factors in Murrieta
Murrieta's standout budget factor is the proportional impact fee above 750 square feet — a 1,000 sq ft ADU on a 2,000 sq ft home is billed on roughly a 50% basis, per the city's example, while a unit at or under 750 sq ft avoids impact fees entirely. That threshold is a genuine lever. Our impact-fees guide and cost guide frame the full budget.
Financing your Murrieta ADU
Most homeowners fund ADU construction through a HELOC, cash-out refinance, a construction loan, or some combination — see our ADU financing overview and loan payment calculator for how each works. Financing options aren't generally city-specific, but a lender may consider your neighborhood and local rents when evaluating projected rental income as qualifying income.
How our process works
Frequently asked questions
An ADU under 750 square feet pays no impact fees. Above 750 square feet, Murrieta charges them proportionately to your primary home's size — the city's example is a 1,000 sq ft ADU on a 2,000 sq ft house billed on a 50% basis. Our impact fees guide explains the statewide 750 sq ft threshold.
A detached ADU can be up to 1,200 square feet; an attached ADU is limited to 50% of your main home's floor area; and a JADU is capped at 500 square feet. California's size floors — 850 sq ft for a studio or one-bedroom, 1,000 sq ft for two or more bedrooms — still apply as a guarantee, so a small percentage result can't shrink your unit below them.
Yes — Murrieta runs a Pre-Approved ADU Program (Information Bulletin IB-113) intended to speed up permitting, with plans prepared by architects, engineers, and draftspersons. Where a pre-approved plan suits your lot, it can cut design time and cost. Confirm current availability with Building & Safety.