Is your Wildomar home near the Wildomar fault?

Wildomar shares its name with a fault. But that alone cannot tell you whether a particular home is in a regulated zone. Only an address check against the official map can.

Does the shared name put every Wildomar home in the zone?

No, the shared name does not place every Wildomar property in an Alquist-Priolo Earthquake Fault Zone.

The Wildomar fault is a named strand of the larger Elsinore fault zone. United States Geological Survey record 126d says the Temecula section includes the Wildomar, Willard, Wolf Valley and Murrieta Creek faults. It also says Engel first used the Wildomar and Willard names in 1933.

That regional description is not a parcel map. The California Geological Survey says Alquist-Priolo zones can run for miles but average about a quarter mile wide. They do not cover every part of an affected city.

Distance from I-15, a nearby fault trace or the city’s name cannot settle the question for your property. You need to check whether the parcel intersects the boundaries on an official Earthquake Fault Zone map.

What is an Alquist-Priolo Earthquake Fault Zone?

An Alquist-Priolo Earthquake Fault Zone is a state regulatory area around the surface traces of an active fault.

For the Alquist-Priolo Act, an active fault is one that has ruptured during the last 11,000 years. The law followed the 1971 San Fernando earthquake and has a specific focus: surface fault rupture.

It does not cover earthquake shaking, liquefaction or landslides. Those hazards fall under the Seismic Hazards Mapping Act, so one map cannot answer every earthquake-related question about a property. The California Geological Survey explanation describes the distinction and how these zones affect development.

Before permitting new projects within a zone, local agencies must require a geologic investigation prepared by a California-licensed geologist. This applies to all land divisions and most structures intended for human occupancy. A structure for human occupancy cannot be placed over the fault and generally must sit at least 50 feet from it. Local agencies may set stricter requirements.

The setback rule is about placing new buildings. For questions about an existing home’s construction, see whether a California house needs an earthquake retrofit.

Where does the city place the Wildomar fault?

The City of Wildomar places the fault approximately 2,000 to 4,000 feet west of I-15, running northwest and southeast through the city.

The city’s Safety Element says the Elsinore fault zone passes through Wildomar on the west side of I-15 and includes the Wildomar and Wolf Valley faults. It describes the zone as capable of generating earthquakes from magnitude 6.5 to 7.5.

The Safety Element says areas next to the Wildomar fault are within a regulated zone, but it uses the former name “Special Studies Zone.” California once used that term. Official maps issued after June 1, 1995 use “Earthquake Fault Zones,” and the current name is Alquist-Priolo Earthquake Fault Zone.

The city adopted the Safety Element on October 13, 2021, and amended it on November 20, 2024. The document also identifies two potentially active faults near the city: the Agua Caliente Fault zone and the Murrieta Hot Springs Fault. It does not say that either one is within an Alquist-Priolo zone.

The Safety Element reports that Wildomar has experienced noticeable ground movement without local damage. It identifies the main Elsinore trace’s one historical event above magnitude 5.2 as the 1910 magnitude 6 earthquake near Temescal Valley.

What evidence does the USGS report for the Wildomar fault?

The United States Geological Survey reports fault-related landforms, faulted deposits and trench evidence along the Wildomar fault.

The northern end of the Temecula section includes the Willard and Wildomar faults along the south side of Lake Elsinore. USGS record 126d describes the broader zone as right-lateral, or strike-slip, and part of the San Andreas fault system. It reports Holocene activity along the fault zone and movement of about 4 to 5 millimeters per year.

Landforms mapped on the Wildomar fault include scarps, sag ponds and a raised block called a horst. The record also identifies faulted Holocene alluvium and the late Pleistocene Pauba Formation.

A trench south of Lake Elsinore showed deformation interpreted as evidence of two earthquakes, and possibly three. It also lists Alquist-Priolo maps for the Elsinore, Murrieta, Pala, Pechanga, Temecula and Wildomar quadrangles among the sources used to locate fault traces.

None of those regional findings determines whether a particular house falls inside the regulatory boundaries.

What does Policy S-5 require?

Policy S-5 requires geologic trenching studies within designated Earthquake Fault Zones unless the City Engineering Geologist accepts adequate evidence instead.

The policy appears in Wildomar’s Safety Element. It also calls for geologic studies for critical, high-occupancy and school structures within 0.5 miles of Quaternary-to-historic faults shown on the zones map.

This requirement applies to development review at mapped locations. It is not a blanket finding about existing homes west of I-15. The state framework similarly applies to land divisions and most new structures intended for human occupancy within a zone.

If you are considering an addition, replacement structure or land division, ask what the city requires for that project and parcel. A general map description cannot replace city review or an investigation by a California-licensed geologist.

What must a seller disclose?

A seller must disclose when the property being sold intersects an Alquist-Priolo Earthquake Fault Zone.

The California Geological Survey says sellers and real estate agents must provide a Natural Hazard Disclosure Statement before the sales process is complete. If no agent is involved, the seller must inform the buyer directly. CGS identifies the Natural Hazard Disclosure Statement as the form described in Civil Code 1103.2.

A Real Estate Transfer Disclosure Statement may be used instead only if it carries what the law calls “substantially the same” information and warning as the Natural Hazard Disclosure Statement.

As a buyer, check the earthquake fault zone entry on the statement and the map information behind it. A zone disclosure identifies a mapped regulatory condition. It does not say that the house is unsafe, that a fault lies directly beneath the building or that the property has suffered earthquake damage.

The Natural Hazard Disclosure report overview explains how the report fits into a transaction. For other property statements, see what a California seller must disclose. You can also compare the address with the official state map and ask the city about its records.

How can you check a Wildomar address?

You can check a Wildomar address on the California Geological Survey’s official maps and take unresolved questions to the Wildomar Planning Department.

CGS gives you three ways to review a zone: the EQ Zapp interactive map, official quadrangle map PDFs and paper quadrangle copies at the local planning department. You can find the PDFs in the CGS Information Warehouse under regulatory maps.

Choose the official quadrangle covering the property’s location. Look at the Earthquake Fault Zone boundaries, not only the fault trace. For maps issued after June 1, 1995, read the title block and confirm the quadrangle name and the words “OFFICIAL MAP.” Those maps also display “EARTHQUAKE FAULT ZONES.” Older maps may say “SPECIAL STUDIES ZONES.”

Do not use the city’s estimate of 2,000 to 4,000 feet west of I-15 as a substitute for the map. That measurement gives the fault’s general location, not parcel boundaries.

Wildomar’s Planning Department handles land-use and zoning questions at 951-677-7751. City Hall is at 23873 Clinton Keith Road, Suite 110, and paper quadrangle maps are available through local planning departments.

If the location is unclear, ask which official quadrangle covers the address and whether the parcel intersects the zone. For a development proposal, ask whether Policy S-5 requires trenching or whether the City Engineering Geologist has accepted other adequate evidence.

The short version

Only an official address check can tell you whether a Wildomar property is within an Alquist-Priolo Earthquake Fault Zone.

The Wildomar fault is a named part of the Elsinore fault zone, and the city places it west of I-15. These regulatory zones address surface fault rupture. They do not label every Wildomar home unsafe, and they do not cover shaking, liquefaction or landslides.

Check the official quadrangle map, review the Natural Hazard Disclosure Statement during a sale and contact Wildomar Planning when you need help with the map or development requirements.

For a separate property estimate, use the home value tool.