San Gabriel Valley · LA County
ADU permits in Monrovia
Zip codes:9101691017
Monrovia is an independent city of about 38,000 people in the foothills of the San Gabriel Mountains, between Arcadia and Duarte. It runs its own building and planning departments. The city has a strong historic identity anchored by the walkable Old Town Monrovia commercial district along Myrtle Avenue, a top-rated Monrovia Unified School District (MUSD), and large foothill lots that climb into the Angeles National Forest.
Independent city — not LADBS
Monrovia runs its own building department. Permits go through Monrovia Community Development Department ↗, not the Los Angeles Department of Building and Safety (LADBS). Our address checker pulls real zoning + overlay data for any Los Angeles County address. The Monrovia ordinance breakdown below covers the city-specific permit path.
Monrovia by the numbers
Rounded figures from the 2020 US Census, LA County Assessor parcel data, and the city's own published reports. Estimates only — your specific lot can vary widely.
Population
38,000
2020 Census
Single-family homes
~9,500
LA County Assessor
Median lot size
6,800 sqft
Approximate
Median home value
$1.5M
Zillow / Redfin
What makes Monrovia different
Monrovia's ADU ordinance is in Monrovia Municipal Code Title 17. The city aligns with the California state baseline plus Hillside Standards for foothill parcels. Plan check is typically 45-60 days. Old Town Monrovia has historic-compatibility design review.
Monrovia ADU ordinance — the rules that apply
Last verified: 2026-05-12
The current ADU rules in Monrovia, sourced from the city's published ordinance and verified against CA Government Code §65852.2 (which preempts local rules stricter than state baselines). When you see "state default," that means the city can't reduce below this number under state law.
| Max detached ADU size | 1,200 sqft (state default) |
| Max ADU height | 16 ft / 18 ft with second-story setbacks |
| Setbacks | 4 ft side / 4 ft rear (state minimum) |
| Hillside Standards | Apply on slopes over 10% Lot-coverage + grading rules for north Monrovia foothill parcels. |
| Old Town historic-compatibility design review | Required for parcels in or adjacent to the Old Town district |
| Local processing time | 45-60 days for standard ADUs |
| Pre-approved standard plans | None city-specific |
Active overlays + extra rules in Monrovia
City overlays + state-level designations that hit a meaningful share of Monrovia parcels. Each affects what you can build, how long it takes, or how much it costs.
Very High Fire Hazard Severity Zone (VHFHSZ)
~32% of parcelsNorthern Monrovia foothills + canyon parcels. Chapter 7A construction required.
Hillside Standards
~28% of parcelsSlopes over 10% trigger geotech + grading limits.
Old Town historic district
~6% of parcelsExterior-visible ADUs on contributing parcels face design review.
Watch-outs specific to Monrovia
Patterns we see across MonroviaADU permits. None are dealbreakers — they're just the things people get wrong most often.
- 01
Foothill parcels need geotech reports
Lots above Foothill Boulevard typically need a geotechnical / soils engineering report. Budget $3K-$8K and add 4-8 weeks to the schedule.
- 02
Monrovia Unified school fees apply
Monrovia Unified School District (MUSD) charges school facility fees on ADUs over 500 sqft.
- 03
Old Town design review for visible exteriors
If your lot is in or adjacent to the Old Town district along Myrtle Avenue, exterior-visible ADU elements face historic-compatibility review. Plan for design conversations before drafting.
Need a person, not a wizard?
Routes that fit Monrovia
Based on what we know about Monrovia, these are the lead types that usually make sense here. Pick whichever fits your situation. All free, no obligation.
Complex permit context
Request a Monrovia permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Monrovia usually mean a permit expediter pays for itself in saved months. We work with vetted Los Angeles permit expediters and expeditors (both spellings) who've handled Monrovia projects.
Complex permit context
Request a Monrovia permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Monrovia usually mean a permit expediter pays for itself in saved months. We work with vetted Los Angeles permit expediters and expeditors (both spellings) who've handled Monrovia projects.
Talk to our financing broker
Want someone to walk you through your options?
Our in-house broker has 30+ years in LA mortgage and ADU financing. He'll lay out HELOC, construction-to-perm, and ADU-specific products like Renofi against your situation — free, no obligation.
Talk to our financing broker
Want someone to walk you through your options?
Our in-house broker has 30+ years in LA mortgage and ADU financing. He'll lay out HELOC, construction-to-perm, and ADU-specific products like Renofi against your situation — free, no obligation.
Plans that fit Monrovia lots
Monroviadoesn't maintain a city-specific pre-approved plan library the way the Los Angeles Department of Building and Safety (LADBS) does. California Department of Housing and Community Development (HCD)-approved prefab (which bypasses local plan check) and custom designer plans are the main paths:
Amenities + civic services in Monrovia
Parks, libraries, and the school district that serve the area. Context that matters for renter appeal, family relocation, and long-term resale.
Parks + sports
Recreation Park
Mayflower Avenue, central Monrovia
Monrovia's main community park. Recreation center, baseball, soccer, pool, and a disc-golf course.
Disc golf course + public pool
- Disc Golf
- Pool
- Baseball
- Soccer
- Playground
- Community Center
- Picnic
Library Park
Myrtle Avenue, downtown Monrovia
Compact downtown park adjacent to the Monrovia Public Library. Hosts the summer Concerts in the Park series.
- Amphitheater
- Playground
- Picnic
Monrovia Canyon Park
Northern foothills, Canyon Boulevard
80-acre hillside park with hiking trails up Monrovia Canyon to Monrovia Falls.
- Trails
- Picnic
Libraries
Monrovia Public Library
Other
Myrtle Avenue, downtown
Independent Monrovia Public Library, not part of LA County Library.
Public schools
School assignments vary by exact address. The district + notable schools below cover most of the area.
District
Monrovia Unified School District (MUSD)
Notable schools in the area
- Monrovia High School
- Clifton Middle School
MUSD is well-regarded — a primary driver of Monrovia home premiums.
Getting around Monrovia
Walkable around Old Town + the Metro A Line station. Foothills are car-dependent.
Transit + walkability
Metro Rail
- A Line (Gold Line) — Monrovia Station
Bus lines
- Foothill Transit Routes 187 + 690
Walkability
Old Town Monrovia + the Station Square area are walkable. Foothill north is car-dependent.
Transit parking exemption applies. Lots within ½ mile of a major transit corridor skip the off-street parking requirement for Accessory Dwelling Units (ADUs) under California state rules. Confirm with the city or county that your specific parcel qualifies.
Nearby airports
Distance + type for each major Los Angeles-area airport reachable from Monrovia. Useful for travel, commute, and any flight-path noise concerns on specific parcels.
Hollywood Burbank Airport (BUR)
~18 miRegional / domestic
Los Angeles International (LAX)
~30 miInternational
Community + landmarks in Monrovia
Annual events, landmarks, and the places that anchor the area's identity. Context for renter appeal and long-term resale.
Annual events
What makes Monrovia Monrovia
Walkable district
Old Town Monrovia
Restored late-1800s commercial main street along Myrtle Avenue. Independent shops, dining, and Family Festival night every Friday.
Hiking destination
Monrovia Canyon Park + Falls
Foothill canyon hike to Monrovia Falls. Family-friendly trail.
Nearby areas to Monrovia
Other Los Angeles-area pages worth a look. Each one runs different Accessory Dwelling Unit (ADU) rules depending on jurisdiction — we show you what changes when you cross a city or county line.
Independent city
Arcadia →
Large foothill lots, top-ranked Arcadia Unified School District (AUSD), and Metro A Line (Gold Line) access drive strong Accessory Dwelling Unit (ADU) economics. Northern foothill parcels face Hillside Standards + Very High Fire Hazard Severity Zone (VHFHSZ) rules.
Independent city
Pasadena →
Large bungalow-belt lots support strong Accessory Dwelling Unit (ADU) economics, but Pasadena's Landmark Districts cover a meaningful share of the city and add design-review time to any exterior-visible ADU.
Frequently asked questions about Monrovia ADUs
›Can I build an ADU in Monrovia?
Yes. Monrovia allows ADUs under its local ordinance, aligned with California Government Code §65852.2 (the state baseline that preempts overly-strict local rules). Most single-family lots can host one ADU plus one JADU. Permits go through Monrovia Community Development Department, not LADBS — see the ordinance table above for the specific rules.
›How does Monrovia differ from LA City for ADU permits?
Three main differences: the permit agency (Monrovia Community Development Department vs. LADBS), the local ordinance details (each city has some flexibility above the state baseline), and the timeline (some cities are faster, some slower than LA's 60-day plan check). See the ordinance breakdown above for the specifics on each.
›How much does it cost to build an ADU in Monrovia?
Median home value in Monrovia is around $1.5M, which usually means lot economics support a quality ADU build of $200K–$400K all-in. Hillside, coastal, or VHFHSZ lots add 7–25% on top. HCD-prefab units (Connect Homes, Cover, Plant Prefab) bypass local plan check entirely and typically run $190K–$350K turnkey.
›Does Monrovia have pre-approved standard plans like LA's YOU-ADU?
No. Unlike LADBS, Monrovia does not maintain a city-specific pre-approved plan library. The two faster paths are an HCD-approved prefab (factory-certified, skips local plan check) or a custom designer drawing for your lot. The slower path is a fully custom architect-led design.
›Will the PermitPathLA wizard work for my Monrovia address?
Yes. The wizard pulls real zoning, overlay, and parcel data for any Los Angeles County address, including Monrovia. What you'll see today: feasibility for your specific lot, the overlays that apply, and a routing summary pointing at Monrovia Community Development Department for the permit submittal. Deeper Monrovia-specific permit walkthroughs are next on the roadmap as we expand from LADBS into the independent-city ordinances.
Ready to see what your Monrovia lot can do?
Our free address checker pulls real zoning, overlay, and parcel data for any Los Angeles County address — including Monrovia. Start there and we'll surface what applies to your specific lot.
Check your address →Reviewed by Yair Harpaz, Founder, PermitPathLA. California DRE-licensed broker with 30+ years of Los Angeles real estate and mortgage industry experience.
Monrovia ordinance data last reviewed .
See an error or stale rule? corrections@permitpath.la
Primary sources: Monrovia planning · Monrovia Community Development Department permits