Building permits, zoning and septic rules in Monterey County, California

At a glance

Building permit

Required in unincorporated Monterey County for nearly any structure¹

Zoning

Yes, countywide — Title 21 inland, Title 20 coastal⁶

Septic authority

Monterey County Health Department, Environmental Health Bureau⁷

Septic soils

Only 2.6% of soils rate free of severe limits for a conventional drain field⁸

Owner-builder

Allowed; exempt from contractor licensing if you do or directly hire the work, but permits still apply⁹¹⁰

RV living

Prohibited as a dwelling on private property, even short-term¹¹

Tiny / manufactured home

Parcel-specific; coastal districts may allow a qualifying tiny or manufactured home as an ADU, inland ADUs may be barred where water, sewer, traffic or safety is inadequate¹²¹³

Lot and home size

Lot size is district-specific, from 5,000 sq ft up to 160 acres; we could not confirm a general minimum home size¹⁴

Wells

Monitoring borings left in place over 72 hours need a county permit; domestic well rules unconfirmed¹⁵

Who to call

Contact details are copied from each office’s official page and were checked against it on October 16, 2026.

Do you need a building permit in Monterey County, California?

Unincorporated Monterey County requires a construction permit for nearly any structure, including a new home, an addition or most outbuildings¹. Some uses and structures also need a separate planning permit even when a construction permit is not required¹⁶. Monterey County's housing element records the county's adoption of the 2022 California Building Code and related state codes, subject to county provisions and local amendments¹⁷. California's 2025 Building Standards Code applies statewide to permit applications filed on or after January 1, 2026, so ask Building Services which code cycle and local amendments govern your filing¹⁸¹⁶. Building permit fees follow the county's fee schedule adopted February 3, 2026, and vary by project type and construction valuation; single-family plan check costs 65% of the building inspection fee, and the schedule adds a 15% General Plan Management Fee and a 13% Technology Fee¹⁹. Which permits apply also depends on the zoning district and proposed use because separate inland and coastal zoning ordinances cover unincorporated land³.

Who is the Monterey County building department, and how do you reach them?

Monterey County's building department is Housing & Community Development (HCD) Building Services, part of the county's Permit Center at 1441 Schilling Place, 2nd Floor, Salinas, CA 93901¹⁶. Reach the Permit Center at (831) 755-5025; the county's own FAQ page gives Permit Center hours as 8 am to 4 pm, Monday through Friday¹⁶. The same Permit Center houses Planning Services, so a call to (831) 755-5025 can route you to either building or planning staff depending on what your project needs²⁰. Development Services, also based at the Schilling Place office, issues encroachment permits for any driveway or other work that crosses a county road right-of-way²¹. A driveway onto a county highway needs a written permit from the Public Works Director, and the driveway may not sit within an intersection's curve returns²². The encroachment application expires 365 days after filing unless a permit issues, and inspection must be scheduled at least 48 hours before work²³. If a parcel sits near mapped water, Permit Center staff at the same office determine whether it falls inside a FEMA Special Flood Hazard Area before you design a foundation²⁴.

Does Monterey County have zoning?

Monterey County zones its unincorporated land, with Title 21 setting standards inland and Title 20 in the coastal zone⁶². Those rules stop at city limits: Salinas and Soledad set their own zoning²⁵²⁶, while septic and wells for every address stay with county or state health authorities⁴. Minimum lot size runs from about 5,000 square feet in a High Density Residential district up to 40–160 acres in agricultural and grazing districts¹⁴. Setbacks, lot coverage and building height also vary by district and may be affected by special standards or exceptions²⁷²⁸²⁹. Inland ADUs and junior ADUs are allowed only in qualifying zoning districts and remain subject to building, zoning, wastewater and other permits; Monterey County also prohibits ADUs in some unincorporated areas where water or sewer service is inadequate or traffic and safety impacts prevent them¹². Land the zoning maps do not name falls in the U District³⁰². We found no general minimum home size; the one size rule we confirmed covers single-room-occupancy units in HDR districts, which need a Use Permit and run 150 to 400 square feet excluding bathroom and closet, for no more than two people³¹. The coastal version of that rule is a public draft, so ask Planning Services whether it has been adopted³²²⁰. Along the Carmel River in Carmel Valley, development within 200 feet of the riverbanks, in the floodway or in the riparian corridor is prohibited unless a stated exception is met, and all development within 200 feet of the banks needs a Use Permit³³. Planning Services can identify the zoning designation through its lookup system or by phone before you design around a parcel²⁰.

How do septic permits work in Monterey County?

The Monterey County Environmental Health Bureau regulates onsite wastewater treatment systems in the unincorporated county under the county's approved Local Agency Management Program⁴. A county installation permit is required for an OWTS handling domestic wastewater discharge of 10,000 gallons per day or less³⁴. Off-grid does not mean permit-free: constructing, replacing, modifying or abandoning an OWTS requires applicable permits, and most onsite treated nonpotable-water systems need a county plumbing permit before installation⁵. Only 2.6% of Monterey County soils are rated free of severe limits for a conventional drain field, so establish wastewater feasibility before committing to a building site⁸. The Environmental Health Bureau's Land Use program reviews development projects and building permits for compliance where the bureau has oversight³⁵. A final inspection is required before piping or components are covered with earth, requests need at least 48 hours' notice, and the system may not be used until the Environmental Health Bureau grants final approval³⁶. A structure within 300 feet of a sewer main generally must connect to it, unless it is served by a lawfully functioning OWTS or another listed exception applies³⁷. Repairs as defined in Chapter 15.20 do not need an OWTS installation permit³⁸. Wells are a separate matter: a groundwater monitoring boring used for septic site evaluation that stays in place more than 72 hours needs its own county monitoring-well permit¹⁵. The county's rules for a domestic water well were not confirmed; California leaves well permitting to local enforcing agencies such as the county environmental health department³⁹. The county may also require an operating permit when routine monitoring or maintenance is necessary⁴⁰.

Can you live in an RV or tiny home on your land in Monterey County?

Monterey County prohibits using a trailer, camper, RV or boat as a dwelling or temporary guest room while it is parked or stored on private property in the unincorporated county¹¹. A tiny home has no single countywide path: its legal treatment depends on whether it qualifies as approved housing, a manufactured home or an ADU and whether the parcel's zoning and services support that use⁴¹¹². Inland ADUs remain subject to building, zoning and wastewater approvals and are prohibited in some areas with inadequate water or sewer service or traffic and safety constraints¹². A separate coastal ordinance can allow a qualifying tiny home or manufactured home (as defined in California Health and Safety Code section 18007) as an ADU in listed coastal districts, but only with Environmental Health Bureau approval of sewage and water and not until the Coastal Commission certifies it and the county confirms the Board's action⁴²¹³. Ask Planning Services to classify the unit and confirm the parcel before buying it²⁰.

Building a home in Monterey County: the steps, in order

1. Confirm the zoning district and its lot-area, setback, coverage and height standards with HCD Planning Services²⁹²⁰.
2. Ask Permit Center staff whether the parcel is in a FEMA Special Flood Hazard Area before designing the foundation²⁴.
3. Establish water and wastewater feasibility with the Environmental Health Bureau; off-grid sanitation still requires applicable OWTS or plumbing permits⁴³⁵³⁷.
4. Apply through HCD Building Services for the construction permit and any separate planning permit the use requires¹⁶.
5. Apply for an encroachment permit if the driveway or other work enters a county road right-of-way²¹.
6. If building as an owner-builder, review the county's owner-builder notice before hiring labor⁴⁴. State law exempts an owner from contractor licensing when none of the work is intended or offered for sale and the owner does it personally or hires licensed trade contractors directly; for single-family projects no more than four structures may be offered for sale in a calendar year, and a homeowner improving a principal residence must have lived there for 12 months before completion¹⁰. That exemption does not waive building permits, inspections, zoning or septic approvals¹⁰.
7. Before final inspection, file the construction and demolition waste recycling report; skipping it can delay the Certificate of Occupancy or final inspection⁴⁵.

What to check before you buy land in Monterey County

Monterey County sits about 24 miles from the nearest city of 100,000 or more, with a countywide population density of 131 people per square mile, so how rural a parcel feels depends heavily on which part of the county it's in⁴⁶⁴⁷. About 45% of the land is wooded and roughly a quarter sits at a gentle 15% slope or less, so check a specific parcel's terrain and tree cover, not just the county average, before assuming it's buildable⁴⁸⁴⁹. Federal land covers about 26% of the county, so confirm a parcel's boundaries against public land before you buy⁵⁰. The county gets about 21 inches of rain a year and has seen severe drought in roughly a third of recent years, which matters for a private well⁵¹⁵². We could not confirm the county's permit rules for a domestic well, so ask the Environmental Health Bureau before drilling³⁵³⁹. Typical home value here is $854,719 and farmland runs about $12,799 an acre, well above what many rural buyers expect, and a typical property tax bill is $4,782 a year at an effective rate of 0.7%^53545556. Because nearly all of the county's soils rate poorly for a conventional septic drain field, budget for a site evaluation and likely an engineered system before you close⁸.

Watch-outs

• Do not assume an ADU is allowed because the parcel is residential: Monterey County bars ADUs in some unincorporated areas with inadequate water or sewer service or traffic and safety constraints¹².
• We could not confirm Monterey County's short-term and vacation-rental rules, the full permit review timeline, or a general minimum dwelling size; call the Permit Center at (831) 755-5025 before you budget a project¹⁶.
• A draft county ordinance would exempt one small agricultural building on a qualifying lot of record from a construction permit, but it has not been confirmed as adopted; ask Building Services whether it has taken effect before assuming an ag building needs no permit¹⁶.

Sources

1. Monterey County HCD – Building & Planning Services FAQs (2026 county census)
2. Zoning Ordinance No. 911, Updated January 7, 1974, quoted and re-checked
3. countyofmonterey.gov, quoted and re-checked
4. Adopted Monterey County Code Chapter 15.20, Sewage Disposal, quoted and re-checked
5. countyofmonterey.gov, quoted and re-checked
6. countyofmonterey.gov (2026 county census)
7. Adopted Monterey County Code Chapter 15.20, Sewage Disposal (2026 county census)
8. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
9. Owner - Builder Notice & Information (2026 county census)
10. California Business and Professions Code Section 7044, quoted and re-checked
11. Problem Vehicle Report, quoted and re-checked
12. countyofmonterey.gov, quoted and re-checked
13. Ordinance, coastal ADU/JADU, quoted and re-checked
14. countyofmonterey.gov, quoted and re-checked
15. countyofmonterey.gov, quoted and re-checked
16. Monterey County Housing & Community Development (HCD) — Building Services (countyofmonterey.gov)
17. 2023–2031 Housing Element, Chapter 3: Housing Constraints, quoted and re-checked
18. Approved Building Standards (California statewide rule), quoted and re-checked
19. 2026 Adopted Building Fee Article XIX, quoted and re-checked
20. Monterey County HCD — Planning Services (countyofmonterey.gov)
21. Monterey County HCD Development Services — Encroachment Permits (countyofmonterey.gov)
22. Monterey County Code Section 14.04 Encroachment Permit Provisions, quoted and re-checked
23. Application For Encroachment Permit, quoted and re-checked
24. Monterey County HCD Permit Center (floodplain determinations) (countyofmonterey.gov)
25. Salinas: Salinas Code Sec. 37-10.260 B definitions (Monterey County), quoted and re-checked
26. Soledad: Soledad Municipal Code 17.10.040 R-1 property development standards (Monterey County), quoted and re-checked
27. 2023–2031 Housing Element, Chapter 3: Housing Constraints, quoted and re-checked
28. countyofmonterey.gov, quoted and re-checked
29. 2023–2031 Housing Element, Chapter 3: Housing Constraints, quoted and re-checked
30. Monterey County Zoning Ordinance No. 911, quoted and re-checked
31. 2023–2031 Housing Element, Chapter 3: Housing Constraints, quoted and re-checked
32. EXEMPT - T20 Public DRAFT Part 1 2025 Redline 052925, quoted and re-checked
33. Monterey County Zoning Ordinance — Title 21, Section 21.64.130 Carmel Valley Floodplain, quoted and re-checked
34. Adopted Monterey County Code Chapter 15.20, Sewage Disposal, quoted and re-checked
35. Monterey County Health Department — Environmental Health Bureau (Land Use) (countyofmonterey.gov)
36. EXEMPT - ADOPTED LCP-3-MCO-24-0039-1, quoted and re-checked
37. countyofmonterey.gov, quoted and re-checked
38. countyofmonterey.gov, quoted and re-checked
39. Well Standards (California statewide rule), quoted and re-checked
40. Adopted Monterey County Code Chapter 15.20, Sewage Disposal, quoted and re-checked
41. Information Bulletin 2016-01: Tiny Homes (California statewide rule), quoted and re-checked
42. Ordinance, coastal ADU/JADU, quoted and re-checked
43. Land Use (formerly EHRS), quoted and re-checked
44. Owner - Builder Notice & Information, quoted and re-checked
45. Construction And Demolition (C&D) Diversion Requirements, quoted and re-checked
46. Straight-line distance from the county center to the nearest city of 100,000+ people: Bolthole Index county data
47. Population density: Bolthole Index county data
48. Wooded share of land: Bolthole Index county data
49. Share of land at 15% slope or less: Bolthole Index county data
50. Federal land share: Bolthole Index county data
51. Annual precipitation: Bolthole Index county data
52. Share of years in severe drought: Bolthole Index county data
53. Typical home value (Zillow): Bolthole Index county data
54. Farmland value per acre (USDA census): Bolthole Index county data
55. Median property tax bill: Bolthole Index county data
56. Effective property tax rate: Bolthole Index county data

Written October 16, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.