A lot line adjustment in California moves a property line between neighboring parcels without creating a new lot. The question of where your lines run can come up before an addition, a new fence, an ADU or a sale. On a mid-century lot, the starting points are the recorded maps, a licensed land surveyor and your city's process.
This guide covers where to find recorded maps and records of survey, what state law says about hiring a surveyor and filing a survey, and how lot line adjustments work under the Subdivision Map Act, with Mountain View and Palo Alto as examples. Rules are as of November 2026.
Start with the recorded maps
Recorded maps come in several kinds, including subdivision maps, parcel maps, records of survey and corner records. In some counties you can look at them yourself.
San Mateo County is a good example of what's available:
The Assessor-County Clerk-Recorder says its Property Maps portal lets you download Assessor's maps or recorded maps, such as subdivision maps and parcel maps, online for free. You can search by address, by assessor's parcel number, or by volume and page.
The same maps are available at the County Recorder Division, where you can buy an official copy.
County Public Works reviews all records of survey and corner records in the county, according to its surveying and map checking page. Its field books, right-of-way maps and miscellaneous records aren't online, can be researched on site in Redwood City, and the county says "all survey research must be performed by the surveyor / engineer."
In Santa Clara County, the county's research page says record maps can be found on the County Surveyor's record index map and bought from the Clerk-Recorder's Office. Search tools differ by county, so ask your own county surveyor or recorder.
Keep in mind that an Assessor's map and a recorded subdivision map are different documents. If the question is where your line runs on the ground, that's a job for a licensed surveyor, not a map you download. If your lot also carries old deed restrictions, our post on restrictive covenant modification explains how to find the tract's recorded documents.
Hiring a licensed land surveyor
Under the Professional Land Surveyors' Act (Business and Professions Code sections 8700 to 8805), it's unlawful to practice or offer land surveying in California without a license or a specific exemption (section 8725). Section 8726 says land surveying includes locating, establishing or retracing "any property line or boundary of any parcel of land, right-of-way, easement," and setting or replacing the monuments that mark a property line or corner.
The Board for Professional Engineers, Land Surveyors, and Geologists (BPELSG) publishes a consumer guide that lists what licensed land surveyors can do, including:
perform boundary line adjustments;
replace lost or obliterated property corners;
set boundary markers or property corners, also known as monuments;
retrace boundaries for fences and other purposes;
prepare legal descriptions and maps or plats for plot plans;
determine boundary discrepancies.
The guide adds that a survey made only for geological or landscaping purposes, which doesn't determine property lines, doesn't require a licensed land surveyor. It also says civil engineers licensed before January 1, 1982 may perform land surveying services if they are competent.
Before you hire anyone:
Check the license. BPELSG's license lookup page explains how to check the current status of a land surveyor through the state's DCA Search. BPELSG's guide says you can also find out whether there have been complaints or disciplinary actions.
Get a written contract. Section 8759 requires a licensed land surveyor to use a written contract, signed before work starts unless the client knowingly states in writing that work may begin first. It must describe the services, the basis of compensation and method of payment, the surveyor's name, address and license number, how additional services will be handled, how either side can end the contract, and whether the surveyor carries professional liability insurance.
Look for the seal. BPELSG's guide says land surveying maps, plats, reports and descriptions must carry the surveyor's signature, seal or stamp and the license expiration date.
When a survey becomes a public record
Section 8762 explains why an older survey of your street may already be on file, and why yours might be too. After a field survey, a licensed land surveyor may file a record of survey with the county surveyor. The surveyor must file one relating to land boundaries or property lines if the field survey discloses, among other things:
material evidence or a physical change that doesn't appear on any previously recorded subdivision map, official map or record of survey;
a material discrepancy in the position of points or lines, or in dimensions, compared with those records;
evidence that might result in materially alternate positions of lines or points shown on those maps;
the establishment or retracement of points or lines not shown on any such map, whose positions can't be found from inspecting it.
The record must be filed within 90 days after setting boundary monuments or within 90 days after finishing the field survey, whichever comes first, with an extension if delays are beyond the surveyor's control. The county surveyor examines it and then files it with the county recorder. Ask your surveyor at the start whether your job is likely to need a record of survey.
How a lot line adjustment works under state law
Government Code section 66412(d) says the Subdivision Map Act doesn't apply to "a lot line adjustment between four or fewer existing adjoining parcels," where land taken from one parcel is added to an adjoining parcel and no greater number of parcels than originally existed is created, if the local agency or advisory agency approves it. As of November 2026, the section also says:
The city or county must limit its review to whether the resulting parcels will conform to the local general plan, any applicable specific or coastal plan, and zoning and building ordinances.
It may not impose conditions or exactions except to meet those rules, to require prepayment of real property taxes before approval, or to help relocate existing utilities, infrastructure or easements.
No tentative, parcel or final map may be required as a condition of approval.
The adjustment "shall be reflected in a deed, which shall be recorded."
No record of survey is required unless section 8762 requires one.
The agency approves or disapproves it under the Permit Streamlining Act.
A lot line adjustment is not a lot split. If you want to create a new parcel, our guide to an SB 9 lot split on an Eichler lot covers that path.
Two city processes: Mountain View and Palo Alto
Mountain View. The city's development permits site says a lot line adjustment can be approved administratively by City staff, and the number of parcels afterward can't exceed the number before. Approval has two parts: a Planning Division application, then a Public Works application for a grant deed and Notice of Lot Line Adjustment. As posted when we read it, Nov 6, 2026, the fees were $3,750 for Planning and $3,963.04 for Public Works, and the city lists a typical 2 months for approval plus 2 months to finalize for recording.
The plat and legal description must be prepared by a registered civil engineer or land surveyor. Planning also asks for a scaled plot plan and a preliminary title report.
The city says the Notice of Lot Line Adjustment "does not revise the property lines by itself." A grant deed is required with the notice to change the lines.
A title company records the notice with the updated grant deed at the Santa Clara County Clerk-Recorder.
Palo Alto. Palo Alto Public Works says a Certificate of Compliance "is a simplified method to remove, adjust or confirm parcel lot lines." Its lot line adjustment instructions, revised November 9, 2018, were still the posted version when we checked in November 2026. They describe two steps:
Initial submittal: an application signed by all record owners, a fee from the current municipal fee schedule, a preliminary title report current within 3 months, the recorded grant deed and chain of title, a soils report waiver form, and six copies of a preliminary map showing lot layout, dimensions, easements, buildings and any water wells.
Exhibit plan check: a legal description, plat map, new grant deeds from a title company, a lot closure summary and a checklist, wet-signed and stamped by a civil engineer licensed before January 1, 1982, or a licensed land surveyor.
The City Attorney's Office then prepares the certificate and sends it to the Santa Clara County Recorder's Office for recording. The city calls the pamphlet informal and says state law and city ordinances govern. Forms, fees and timelines differ by city, so ask your own planning or public works department.
This is general information as of November 2026, not legal advice. If you and a neighbor disagree about where a line runs, talk with a licensed land surveyor and an attorney before you build or move anything. Our post on the good neighbor fence law covers shared fences.
Frequently asked questions
Can I find my property lines from the county's online maps?
Online maps show how your lot was mapped. Locating or retracing a property line is land surveying under Business and Professions Code 8726, which requires a license.
How many parcels can a lot line adjustment involve?
Under Government Code 66412(d), four or fewer existing adjoining parcels, and the adjustment can't create more parcels than existed before. The local agency must approve it, and the result is recorded in a deed.
Will my survey be recorded?
Sometimes. Under section 8762, a surveyor must file a record of survey when the field survey finds things such as a material discrepancy with recorded maps or sets points not shown on them. It's filed with the county surveyor within 90 days and then with the county recorder.
Do I need a surveyor to stake a new landscape bed?
Not if it doesn't involve property lines. BPELSG's guide says a survey made only for landscaping purposes, without determining property lines, doesn't require a licensed land surveyor.
Related reading
Restrictive Covenant Modification in California: Old Tract Deeds
Single-Story Overlay Districts: Check Your Street, Know the Rules
Mid-Century Modern ADU: Adding a Unit Without Fighting the House
Shared Driveway Easement in California: Utility and Access Easements
More guides on this topic: Owning & Renovating a Mid-Century Modern Home
Thinking about an addition, a lot line change or a sale on a mid-century lot? Call or text the Boyenga Team at Compass at (408) 373-1660 or (650) 383-8606, or contact the Boyenga Team to talk it through.
