MEP Plans in Los Angeles County, CA
Permit-ready mechanical, electrical and plumbing plans for ADUs, garage conversions, additions and single-family homes anywhere in Los Angeles County, in its cities and in unincorporated areas, with Title 24 available in the same order.
Los Angeles County project facts we design around
| County seat | Los Angeles |
|---|---|
| Population | 9,757,179 (Census 2024 estimate) |
| Incorporated cities | 88 |
| Unincorporated residents | About 970,753 (10% of the county) |
| Permits in unincorporated areas | Los Angeles County Public Works – Building and Safety |
| Title 24 climate zones | CZ 9 (about 57% of residents), CZ 8 (about 26% of residents), CZ 6 (about 13% of residents), CZ 14 (about 4% of residents). Confirmed by ZIP for every project |
| ADU approval timeline | Approve or deny within 60 days of a complete application (state law) |
HVAC design across Los Angeles County
Climate Zone 9 and 8: inland climate with hot summers (about 83% of residents)
Summer afternoons regularly push well into the 90s and beyond, so cooling — not heating — sets the equipment size. West-facing glazing, roof insulation and where the ducts run make a large difference to the load. Plan check will expect the Manual J to back up the capacity you show, and the heat pump's electrical load has to be carried through to the panel calculation.
- Cooling-driven Manual J with real window orientation and glazing
- Heat pump and heat pump water heater loads carried into the NEC 220 calc
- Duct location and insulation that match the Title 24 assumptions
Climate Zone 6: coastal, marine-influenced climate (about 13% of residents)
Ocean air keeps summers mild and winters cool rather than cold, so heating and cooling loads are small. The common mistake here is oversizing: a rule-of-thumb unit short-cycles, controls humidity poorly, and wastes panel capacity. A room-by-room Manual J usually supports a compact ducted or ductless heat pump, and in many small units a single well-placed mini-split head does the job.
- Right-size the heat pump from a real Manual J instead of a tonnage guess
- Bath and kitchen exhaust plus whole-unit ventilation sized to ASHRAE 62.2 — tight coastal units trap moisture
- Corrosion-resistant outdoor equipment placement near the ocean
Unincorporated Los Angeles County
Unincorporated communities are permitted by the county, not by a city. County plan check reviews MEP drawings against the same California Mechanical, Electrical and Plumbing Codes and the Title 24 Energy Code as any city, but the submittal checklist, forms and fees are the county's own, so we prepare the set to match. In rural areas, parcels outside a sewer district often rely on a private septic system; adding an ADU can require the county's environmental health division to confirm the system has capacity, and the plumbing plan then shows the connection to the septic tank instead of a sewer lateral.
What's in a Los Angeles County MEP set
- Mechanical: HVAC layout, Manual J load calculation, equipment schedule, exhaust and whole-unit ventilation
- Electrical: power and lighting plan, panel schedule, NEC 220 load calculation, single-line diagram
- Plumbing: supply and DWV layout, fixture units, water heater, gas (if any), sewer or septic connection
- Title 24 (add-on): energy compliance for your address's climate zone, coordinated with the MEP design so the two documents agree
Pricing is flat statewide: ADU plans from $995, full ADU MEP package from $2,295, Title 24 add-on $240. Standard turnaround is 5 business days with two revisions and corrections included.
Los Angeles County cities and communities
| Place | Climate zone | Electric utility |
|---|---|---|
| Acton (unincorporated) | CZ 14, 16 | Southern California Edison (SCE) |
| Agoura Hills | CZ 9 | Southern California Edison (SCE) |
| Alhambra | CZ 9 | Southern California Edison (SCE) |
| Altadena (unincorporated) | CZ 9 | Southern California Edison (SCE) |
| Arcadia | CZ 9 | Southern California Edison (SCE) |
| Arleta (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Artesia | CZ 8 | Southern California Edison (SCE) |
| Avalon | CZ 6 | Southern California Edison (Catalina Island isolated system) |
| Azusa | CZ 9 | Azusa Light & Water |
| Baldwin Park | CZ 9 | Southern California Edison (SCE) |
| Bell | CZ 8 | Southern California Edison (SCE) |
| Bell Gardens | CZ 8 | Southern California Edison (SCE) |
| Bellflower | CZ 8 | Southern California Edison (SCE) |
| Beverly Hills | CZ 9 | Southern California Edison (SCE) |
| Burbank | CZ 9 | Burbank Water and Power |
| Calabasas | CZ 9 | Southern California Edison (SCE) |
| Canoga Park (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Canyon Country (Santa Clarita neighborhood) | CZ 9 | Southern California Edison (SCE) |
| Carson | CZ 6, 8 | Southern California Edison (SCE) |
| Castaic (unincorporated) | CZ 9 | Southern California Edison (SCE) |
| Cerritos | CZ 8 | Southern California Edison (SCE) |
| Chatsworth (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Claremont | CZ 9 | Southern California Edison (SCE) |
| Commerce | CZ 8, 9 | Southern California Edison (SCE) |
| Compton | CZ 8 | Southern California Edison (SCE) |
| Covina | CZ 9 | Southern California Edison (SCE) |
| Cudahy | CZ 8 | Southern California Edison (SCE) |
| Culver City | CZ 8, 6 | Southern California Edison (SCE) |
| Diamond Bar | CZ 9 | Southern California Edison (SCE) |
| Downey | CZ 8 | Southern California Edison (SCE) |
| Duarte | CZ 9 | Southern California Edison (SCE) |
| El Monte | CZ 9 | Southern California Edison (SCE) |
| El Segundo | CZ 6 | Southern California Edison (SCE) |
| Encino (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Gardena | CZ 8 | Southern California Edison (SCE) |
| Glendale | CZ 9 | Glendale Water and Power |
| Glendora | CZ 9 | Southern California Edison (SCE) |
| Granada Hills (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Hacienda Heights (unincorporated) | CZ 9 | Southern California Edison (SCE) |
| Harbor City (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Hawaiian Gardens | CZ 8 | Southern California Edison (SCE) |
| Hawthorne | CZ 8 | Southern California Edison (SCE) |
| Hermosa Beach | CZ 6 | Southern California Edison (SCE) |
| Hidden Hills | CZ 9 | Southern California Edison (SCE) |
| Huntington Park | CZ 8 | Southern California Edison (SCE) |
| Inglewood | CZ 8 | Southern California Edison (SCE) |
| La Cañada Flintridge | CZ 9 | Southern California Edison (SCE) |
| La Habra Heights | CZ 8 | Southern California Edison (SCE) |
| La Mirada | CZ 9 | Southern California Edison (SCE) |
| La Puente | CZ 9 | Southern California Edison (SCE) |
| La Verne | CZ 9 | Southern California Edison (SCE) |
| Lakewood | CZ 8 | Southern California Edison (SCE) |
| Lancaster | CZ 14 | Southern California Edison (SCE) |
| Lawndale | CZ 8 | Southern California Edison (SCE) |
| Littlerock (unincorporated) | CZ 14 | Southern California Edison (SCE) |
| Lomita | CZ 6 | Southern California Edison (SCE) |
| Long Beach | CZ 6, 8 | Southern California Edison (SCE) |
| Los Angeles | CZ 9, 8, 6, 16 | Los Angeles Department of Water and Power (LADWP) |
| Lynwood | CZ 8 | Southern California Edison (SCE) |
| Malibu | CZ 6 | Southern California Edison (SCE) |
| Manhattan Beach | CZ 6 | Southern California Edison (SCE) |
| Maywood | CZ 8 | Southern California Edison (SCE) |
| Mission Hills (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Monrovia | CZ 9 | Southern California Edison (SCE) |
| Montebello | CZ 9 | Southern California Edison (SCE) |
| Monterey Park | CZ 9 | Southern California Edison (SCE) |
| Newhall (Santa Clarita neighborhood) | CZ 9 | Southern California Edison (SCE) |
| North Hills (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| North Hollywood (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Northridge (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Norwalk | CZ 8 | Southern California Edison (SCE) |
| Pacific Palisades (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Pacoima (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Palmdale | CZ 14 | Southern California Edison (SCE) |
| Palos Verdes Estates | CZ 6 | Southern California Edison (SCE) |
| Panorama City (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Paramount | CZ 8 | Southern California Edison (SCE) |
| Pasadena | CZ 9 | Pasadena Water and Power |
| Pico Rivera | CZ 9 | Southern California Edison (SCE) |
| Playa del Rey (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Pomona | CZ 9 | Southern California Edison (SCE) |
| Porter Ranch (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Rancho Palos Verdes | CZ 6 | Southern California Edison (SCE) |
| Redondo Beach | CZ 6 | Southern California Edison (SCE) |
| Reseda (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Rolling Hills | CZ 6 | Southern California Edison (SCE) |
| Rolling Hills Estates | CZ 6 | Southern California Edison (SCE) |
| Rosemead | CZ 9 | Southern California Edison (SCE) |
| Rowland Heights (unincorporated) | CZ 9 | Southern California Edison (SCE) |
| San Dimas | CZ 9 | Southern California Edison (SCE) |
| San Fernando | CZ 9 | Southern California Edison (SCE) |
| San Gabriel | CZ 9 | Southern California Edison (SCE) |
| San Marino | CZ 9 | Southern California Edison (SCE) |
| San Pedro (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Santa Clarita | CZ 9, 16 | Southern California Edison (SCE) |
| Santa Fe Springs | CZ 9 | Southern California Edison (SCE) |
| Santa Monica | CZ 6 | Southern California Edison (SCE) |
| Sherman Oaks (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Sherwood Forest (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Sierra Madre | CZ 9 | Southern California Edison (SCE) |
| Signal Hill | CZ 6 | Southern California Edison (SCE) |
| South El Monte | CZ 9 | Southern California Edison (SCE) |
| South Gate | CZ 8 | Southern California Edison (SCE) |
| South Pasadena | CZ 9 | Southern California Edison (SCE) |
| Studio City (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Sun Valley (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Sunland (Los Angeles neighborhood) | CZ 16 | Los Angeles Department of Water and Power (LADWP) |
| Sylmar (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Tarzana (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Temple City | CZ 9 | Southern California Edison (SCE) |
| Toluca Lake (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Torrance | CZ 6, 8 | Southern California Edison (SCE) |
| Tujunga (Los Angeles neighborhood) | CZ 16 | Los Angeles Department of Water and Power (LADWP) |
| Valencia (Santa Clarita neighborhood) | CZ 9 | Southern California Edison (SCE) |
| Valley Village (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Van Nuys (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Venice (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Walnut | CZ 9 | Southern California Edison (SCE) |
| West Covina | CZ 9 | Southern California Edison (SCE) |
| West Hills (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| West Hollywood | CZ 9 | Southern California Edison (SCE) |
| Westlake Village | CZ 9 | Southern California Edison (SCE) |
| Whittier | CZ 9 | Southern California Edison (SCE) |
| Wilmington (Los Angeles neighborhood) | CZ 6 | Los Angeles Department of Water and Power (LADWP) |
| Winnetka (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
| Woodland Hills (Los Angeles neighborhood) | CZ 9 | Los Angeles Department of Water and Power (LADWP) |
Shown for most addresses in each city. We also serve Los Angeles County's other 4 cities and every unincorporated community.
Los Angeles County ADU MEP questions
Who issues building permits for an ADU in unincorporated Los Angeles County?
In unincorporated areas, home to about 970,753 residents (10% of the county), ADU and residential permits go through Los Angeles County Public Works – Building and Safety. Inside the county's 88 incorporated cities, that city's own building department reviews the plans instead. We prepare the MEP set for whichever office has jurisdiction over your address.
What Title 24 climate zones are in Los Angeles County?
Los Angeles County spans 4 Title 24 climate zones: CZ 9 (about 57% of residents), CZ 8 (about 26% of residents), CZ 6 (about 13% of residents), CZ 14 (about 4% of residents). Zones follow ZIP-code boundaries, so we confirm the zone from your project address before sizing the HVAC or running the Title 24 report.
Who provides electric service in Los Angeles County?
It depends on the address. In the Los Angeles County places listed on this page, most addresses are served by Southern California Edison (SCE), Los Angeles Department of Water and Power (LADWP), Southern California Edison (Catalina Island isolated system), Azusa Light & Water, Burbank Water and Power, Glendale Water and Power or Pasadena Water and Power. We confirm the serving utility for every project, because service upgrades and new meters are requested from the utility, separately from the building permit.
How much do ADU MEP plans cost in Los Angeles County?
Our pricing is flat across California: single-discipline ADU plans start at $995, a full MEP package for an ADU up to 600 SF is $2,295, and a Title 24 report can be added for $240. Residential (single-family) full MEP packages start at $3,495. Standard turnaround is 5 business days, and corrections are included.
How long does ADU approval take in Los Angeles County?
California law requires local agencies, counties included, to approve or deny a complete ADU permit application within 60 days. Incomplete or inconsistent drawings are the most common reason the clock restarts, which is why MEP plans that match the architectural set, and a Title 24 report that matches the MEP design, matter.
Guides for Los Angeles County projects
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Start My OrderGeneral guidance, not legal advice. Population figures are Census Bureau 2024 estimates; climate zones are from the California Energy Commission's ZIP-code list, weighted by population. Requirements vary by project: confirm with Los Angeles County Public Works – Building and Safety or your city's building department.