General plan
400 sq ft · Studio · 1 ba
Studio
Any city
About 20' × 20' — we derived this from the floor area
Murrieta, Riverside County
Will an ADU fit in your Murrieta back yard?
Enter your address and we will draw your real parcel boundary, subtract the setbacks and your existing house, and show you what is actually left to build on. Then you can drag real ADU sizes onto it to see what works.
- Free
- No account
- No phone number
- Your result first
Aerial: USGS/USDA NAIP
Local context
The Murrieta picture
Home base. Wide range of lot sizes, from older Alta Murrieta tracts to newer hillside builds.
- 27,424Detached single-family homes
- 2000Median year built
- 70%Owner-occupied
- $2,388Median rent
Murrieta permitted 24 ADUs in 2025, against 7 in 2023. Source: state Housing Element annual progress reporting.
The standards
The rules that apply to your lot
Every figure shows its source. Read from MMC §16.44.160 + IB-108 (rev. 5/2024).
- 4ftSide and rear setbackMurrieta code
- 1,200sq ftLargest detached ADU Murrieta allowsMurrieta code
- 30daysDecision deadline on a pre-approved planCalifornia minimum
All 12 standards, with sources
| Standard | Value | Source |
|---|---|---|
| Side setback | 4 ft | Murrieta code |
| Rear setback | 4 ft | Murrieta code |
| Detached height | 16 ft Baseline; higher near transit | California minimum |
| Size the city must allow | 800 sq ft Cities cannot prohibit at least this size | California minimum |
| Largest detached ADU allowed | 1200 sq ft | Murrieta code |
| Distance from your house | No requirement Murrieta’s ADU ordinance and its own information bulletin IB-108 both state no minimum distance between the ADU and your house. The only separation that applies is building-code fire separation. | Murrieta code |
| Parking | 1 space per unit Subject to the state transit exemptions | Murrieta code |
| Junior ADU maximum | 500 sq ft | Murrieta code |
| Owner-occupancy required | No | California minimum |
| HOA can prohibit an ADU | No Gov. Code §66315. Reasonable architectural standards still apply. | California minimum |
| Impact fees | Waived under 750 sq ft A real reason to consider staying just under the threshold. | California minimum |
| Pre-approved plan review | 30 days, ministerial AB 1332. No discretionary review, no hearing. | California minimum |
Anything Murrieta publishes inconsistently is left off this table rather than guessed at. Where that happens we say so in the notes above.
ADU sizes to consider in Murrieta
Realistic sizes to compare, drawn to the same scale.
General plan
600 sq ft · 1 bd · 1 ba
1 Bedroom
Any city
About 25' × 24' — we derived this from the floor area
General plan
800 sq ft · 2 bd · 1 ba
2 Bedroom
Any city
About 31' × 26' — we derived this from the floor area
General plan
1,000 sq ft · 2 bd · 2 ba
2 Bed / 2 Bath
Any city
About 33' × 30' — we derived this from the floor area
General plan
1,200 sq ft · 3 bd · 2 ba
3 Bedroom
Any city
About 40' × 30' — we derived this from the floor area
Via the Pre-Approved ADU Program (IB-113). A pre-approved plan is reviewed ministerially in 30 days — no hearing, no neighbour objection. Bulletin published; no plan catalog located.
Where a footprint is marked approximate we derived it from the published floor area and use it only for siting geometry, never as the building design.
Before you spend
What could stop your project in Murrieta
The geometry is usually the easy part. These are the issues that actually kill projects here.
Zoning data
Zoning map published as PDF only; no public GIS layer found.
We apply the state setback floor to your parcel instead — the conservative choice, and your city cannot require more for a new detached ADU.
Check your parcel is even in the city
Several communities here carry a Murrieta mailing address while sitting in unincorporated Riverside County — which means county permitting, under different standards and timelines.
The single most common planning mistake in this area, and worth two minutes to confirm before you pay anyone for drawings.
By neighborhood
Murrieta neighborhoods
Build era, lot depth, septic versus sewer, association rules and fire zone status all change the answer, and they change neighborhood by neighborhood rather than city-wide. Here is what we know about yours.
How this works
- 1
We find your parcel
Your real lot shape from the Riverside County Assessor, not a square around a pin.
- 2
We subtract the setbacks
Murrieta's setbacks, your house, and the clearance between buildings. Green is what is left.
- 3
You drag a real plan in
Fits, tight, or unlikely — and the best position we can find for it, not wherever you dropped it.
What you actually get
A report on your own parcel, in about a minute, before we ask you for anything.
- Your parcel, not an average. Your real boundary from Riverside County GIS, your house footprint, and the buildable area left after Murrieta's setbacks.
- You see it before you give us anything. The map, the numbers and the fit verdict are on screen first. The email is for keeping a copy.
- One call, from a person. We call you ourselves within one business day to go through it. No call centre, and your number is never resold — see the privacy policy.
Fits2 Bedroom, 800 sq ft
- Lot size
- 7,232 sq ft
- What is on it
- house 1,848 sq ft
- Buildable after setbacks
- 2,858 sq ft
- Side and rear setback
- 4 ft
- Plans that fit
- 3 of 5 we checked
Next: a call to walk through it, then one screened local builder if you want quotes. What it costs.
Computed for an ordinary 60 × 120 ft tract lot with a 40 × 46 ft house, using Murrieta's own setback and separation. Your figures come from your own parcel.
Murrieta ADU questions
How big an ADU can I build in Murrieta?
California requires every city, Murrieta included, to allow an ADU of at least 800 square feet. Whether that size fits on your lot after setbacks and the separation from your existing house is a different question entirely, and it depends on your parcel rather than on the city. That is what the tool answers.
What setbacks apply?
For a new detached ADU, state law caps the side and rear setback at 4 feet, so Murrieta cannot require more. We apply that to your parcel boundary. One honest limitation: we erode the parcel evenly rather than identifying which edge fronts the street, which makes the buildable zone slightly generous at the front — so we disallow front-yard placement in the tool entirely.
Can my HOA stop me?
No. Government Code section 66315 voids HOA covenants that prohibit or unreasonably restrict an ADU on a single-family lot. Your association can still apply reasonable architectural standards, and in practice that means an architectural committee submission running in parallel with your city permit. Budget calendar time, not a fight. Submit to both at once rather than waiting for one to finish.
Do I have to live on the property?
No. AB 976 made the prohibition on owner-occupancy requirements permanent, so neither Murrieta nor the state can require you to live in either unit.
Will an ADU reassess my property taxes?
Building an ADU triggers a reassessment of the new construction only, not of your existing home. Your original Proposition 13 base year value on the house is not disturbed. The assessor adds the value of what you built. We are working on a Murrieta-specific breakdown including how this interacts with any existing special district assessments on your parcel.
Which builder will I be sent to?
One licensed builder, exclusive to Murrieta, and we tell you who they are before we introduce you. We are not a contractor and we do not take a cut of your build — we are paid for the introduction, which is why we have no incentive to talk you into a bigger project than your lot supports.
Other cities we cover
See what fits on your Murrieta lot
Free. You see the result before we ask for anything.