Castaic is an unincorporated community in northern Los Angeles County, at the top of the Santa Clarita Valley along Interstate 5 and around Castaic Lake. It has no city council, so Los Angeles County provides its municipal services. Local children attend Castaic Union School District through eighth grade, then the William S. Hart Union High School District.
Buyers usually skim past the unincorporated part, and it is the detail that changes the most for them day to day. It decides which office issues your building permit and which agency answers when something on your street needs fixing. The other questions people ask about Castaic are the lake, the I-5 commute, school assignment, and where local prices land in the wider valley.
Key Takeaways
– Castaic is unincorporated Los Angeles County. One in ten county residents lives in an unincorporated area (Los Angeles County, 2026).
– I-5 carried about 71,000 vehicles a day just south of Lake Hughes Road in 2024, against 171,000 at Valencia Boulevard (Caltrans, 2024).
– Castaic Union runs kindergarten through grade 8; students enter the Hart district at grade 9 (NCES, 2024-25).
– The Santa Clarita Valley median single-family price was $865,000 in August 2026 (SRAR, 2026).
Where is Castaic, and why isn’t it part of Santa Clarita?
Castaic sits north of the City of Santa Clarita along I-5, and the city has never annexed it. In 2026, Los Angeles County reported “more than 120 unincorporated areas” with “a total population of approximately 1 million residents,” covering roughly 2,600 square miles, about two thirds of the county’s land area (Los Angeles County, Unincorporated Area Services, retrieved September 2026).
Castaic falls in the county’s Fifth Supervisorial District, which the county describes as spanning “2,785 square miles” and including “portions of 20 cities and 83 unincorporated communities” across the San Gabriel, San Fernando, Crescenta, Santa Clarita and Antelope Valleys (Los Angeles County Fifth District, retrieved September 2026). So a Castaic homeowner’s elected local representative is a county supervisor, not a council member.
There is a local body, but it is advisory. The Castaic Area Town Council describes itself as “a non-profit 501c3 volunteer board of directors representing the community of Castaic.” It works “alongside the Los Angeles County Board of Supervisors and various County Departments,” and is “comprised of 10 (ten) elected representatives from 5 (five) regions,” with elections every two years (Castaic Area Town Council, retrieved September 2026).
If you’re comparing this to a community inside city limits, the neighboring Valencia community guide and Newhall guide cover areas that do sit inside the City of Santa Clarita.
What does unincorporated status change for a homeowner?
In practice it changes which agency answers. Los Angeles County states that for unincorporated areas, “municipal services, such as law enforcement, firefighting, animal care and control, trash collection, road maintenance, library services, and parks, are provided by the County” (Los Angeles County, retrieved September 2026).
Law enforcement comes from the Los Angeles County Sheriff’s Department. The Santa Clarita Valley Station at 26201 Golden Valley Road lists Castaic among the communities it serves, alongside the contract City of Santa Clarita and other unincorporated areas including Val Verde, Hasley Canyon and Stevenson Ranch (LASD, retrieved September 2026). Fire and emergency medical response comes from the Los Angeles County Fire Department; Station 149 is listed at 31770 Ridge Route, Castaic (Los Angeles County, retrieved September 2026).
Permits are the part that catches people mid-renovation. Los Angeles County Public Works handles “permitting, and inspection of residential and commercial developments” for unincorporated communities, along with land development plan review, “code enforcement and property rehabilitation programs,” and graffiti removal (LA County Public Works, retrieved September 2026). If you plan to add square footage, convert a garage or put in a pool, that file goes to the County, not to a city counter in Valencia.
How do property taxes work in Castaic?
Unincorporated status does not create a separate tax system. The Los Angeles County Treasurer and Tax Collector describes the Annual Secured Property Tax Bill as a bill “which includes the General Tax Levy, Voted Indebtedness, and Direct Assessments.” It defines a direct assessment as “a non-ad valorem amount charged on a per parcel basis,” and its examples include “garbage collection, sewer, lights and landscaping maintenance, mosquito abatement” as well as “community facilities district charges (Mello-Roos)” (LA County TTC, retrieved September 2026).
The payment calendar is the same countywide. The first installment is due November 1 and is delinquent after the close of business on December 10. The second is due February 1 and delinquent after the close of business on April 10. Each carries a 10% penalty, and the second installment adds a $10.00 cost (LA County TTC, retrieved September 2026).
If Castaic will be your primary residence, claim the Homeowners’ Exemption. The California Constitution “provides a $7,000 reduction in the taxable value for a qualifying owner-occupied home,” and a first-time filer may file “no later than February 15 to receive the full exemption for that year” (California State Board of Equalization, retrieved September 2026). It’s a one-time claim with your county assessor, and it is easy to forget while you’re closing.
Mello-Roos and special assessments
Newer tracts anywhere in the Santa Clarita Valley can carry a Mello-Roos special tax, and Castaic is no exception. Rather than quote a rate that varies parcel by parcel, get the notice. California Civil Code Section 1102.6b requires a seller to “make a good faith effort to obtain a disclosure notice” from the relevant local agency covering Mello-Roos special taxes, 1915 Improvement Bond Act assessments or contractual assessment programs, and to deliver it to the prospective buyer (California Legislative Information, retrieved September 2026). The notice states the current amount, the maximum rate and how much it can rise.
Ask for that notice early in escrow. Two homes at the same list price can carry very different monthly costs once a special tax is added, and that gap shows up in loan qualification as well as in your monthly budget.
What is Castaic Lake, and how do people actually use it?
Castaic Lake is a working reservoir that also happens to be open for recreation. In its Daily Reservoir Storage Summary dated September 10, 2026, the California Department of Water Resources listed Castaic at 325,000 acre-feet of capacity and 304,703 acre-feet of storage, which is 94% of capacity and 112% of the historical average for the date (DWR CDEC, 2026). You can see the water level from a good part of Castaic, and it moves with the season.
Los Angeles County Parks and Recreation runs the Castaic Lake State Recreation Area, with park headquarters at 32132 Castaic Lake Drive. Published rates list vehicle entry at “$15.00 Daily,” senior 65-plus and disabled vehicle entry at “$8.00 Daily,” an RV permit at “$23.00 Daily,” and an annual vehicle pass at “$160.00/Year.” Boating is “$9.00 Daily” non-motorized and “$13.00 Daily” motorized. The county also notes that regional parks are closed Mondays and Tuesdays, that campgrounds are “closed until further notice due to damages sustained during the Hughes fire,” and that all vessels are inspected on exit because of invasive mussels (LA County Parks, retrieved September 2026).
That last set of details matters if the lake is part of why you’re buying. Confirm current hours, closures and boating protocols with the county before you plan around them. The campground closure above is open-ended, and the county’s own page is the only place that will tell you when it lifts.
What is the I-5 commute really like from Castaic?
A drive-time estimate changes hourly. Traffic volume is the more useful number, because it tells you what you’re merging into. Caltrans measured about 71,000 vehicles a day on I-5 immediately south of Lake Hughes Road in 2024, rising to 89,000 south of Parker Road, 108,000 south of Hasley Canyon Road, and 171,000 south of Valencia Boulevard (Caltrans Traffic Census Program, 2024 AADT).
Southbound, you start on the lightest stretch of I-5 in the valley and pick up volume at every interchange. By Valencia Boulevard you’re in nearly two and a half times the traffic you left. Northbound in the evening the same numbers work in your favor, and the load sheds as you climb past Hasley Canyon.
Castaic has three main freeway access points: Hasley Canyon Road, Parker Road and Lake Hughes Road. Which one you live nearest changes your morning, so ask about it while you’re still touring houses.
If you’re moving up from the San Fernando Valley, the drive changes in character as well as in length. The relocating from the San Fernando Valley guide walks through what that shift looks like day to day.
Which schools serve Castaic, and how do I confirm my assignment?
Two districts serve Castaic, split by grade. Federal data for 2024-25 lists Castaic Union School District with a grade span of “KG – 8,” five schools, 1,914 students and a student-teacher ratio of 25.57 (NCES Common Core of Data, 2024-25). The district’s schools are Castaic Elementary, Live Oak Elementary, Northlake Hills Elementary, Castaic Middle School and a preschool (Castaic Union School District, retrieved September 2026).
High school comes from the William S. Hart Union High School District. Castaic High, at 31575 Valley Creek Road, is listed with a grade span of “9 – 12,” 1,159 students, 49.07 full-time-equivalent classroom teachers and a student-teacher ratio of 23.62 (NCES Common Core of Data, 2024-25).
Families transferring in are the ones who get caught by the grade split. The Hart district states that “students in grades 7 and 8 attend junior high school; high schools serve students in grades 9 through 12” (Hart District, retrieved September 2026). Because Castaic Union runs through grade 8, a Castaic student typically finishes middle school inside Castaic Union and enters the Hart district at grade 9, rather than at grade 7, where the Hart district’s own junior highs begin. If you’re moving mid-middle-school, ask both districts how that lands for your child specifically.
The districts set attendance areas, and those change. Confirm your exact address with Castaic Union School District and with the Hart district enrollment office before you write an offer, and treat any boundary information from a listing, a map site or an agent, including this page, as a starting point rather than an answer. The enrollment figures above come from federal reporting for 2024-25 and describe school size rather than school quality.
What does the housing stock look like, and where do prices sit?
No one publishes a Castaic-only price series, so the valley-wide numbers are the honest frame. In August 2026, the Southland Regional Association of REALTORS reported a Santa Clarita Valley median single-family home price of $865,000, down 2.8% year over year, and a condominium median of $520,000, down 10.3%. The association notes that the record high median home price of $910,000 was set in March 2024 (SRAR, September 9, 2026 release).
The rest of that release is what a buyer or seller should plan around. Local REALTORS closed 147 single-family sales in August, down 9.3% year over year, and both the home and condominium totals were the lowest recorded for an August going back to 2020. Active single-family listings fell 24.5% to 518. Homes averaged 45 days on market, five days longer than a year earlier, and pending sales at month end totalled 121, down 30%. New home listings came in at 208, down 10%. The association also cited a national average home loan rate of 6.51% in August as reported by the Federal Housing Finance Agency, up from a 6.08% low in April and down from 6.83% in August 2025 (SRAR, 2026).
Listings fell and days on market rose at the same time, which is the odd part. Thin inventory usually shortens marketing time. When both move the other way, buyers are being selective rather than absent, and preparation and pricing carry more weight than they would in a fast market. That matters more in Castaic than it would in a uniform tract, because the housing stock spans older homes near Ridge Route and newer master-planned neighborhoods around Hasley Canyon, Live Oak and Northlake. Two homes a mile apart here can be twenty-five years and one special tax district apart.
For a fuller read on where the valley sits, see the Santa Clarita Valley market update. Sellers weighing timing may find the guide to selling a Santa Clarita home for top dollar more directly useful.
How does Castaic compare with the rest of the Santa Clarita Valley?
These are structural differences rather than a ranking. Castaic is unincorporated, so the County is your municipal government, and its elementary district runs to grade 8 rather than grade 6. It also sits on the lightest-volume stretch of I-5 in the valley, and it has the lake.
Communities to the south sit inside city limits or have their own character worth comparing directly: Stevenson Ranch, Saugus, Canyon Country and the larger-lot Sand Canyon and Circle J Ranch area. Buyers weighing several at once often find it easier to compare the valley’s neighborhoods side by side than to evaluate one in isolation.
Decide on the things you can verify: commute pattern, school assignment confirmed with the district, the tax bill including any special assessment, lot size and permit history. Those are the items you live with for as long as you own the house.
Thinking about Castaic?
If you want a straight read on a specific street, tract or listing in Castaic, including the tax and school questions above applied to one address, get in touch through the contact page and we’ll go through it together.
Frequently Asked Questions
Is Castaic part of the City of Santa Clarita?
No. Castaic is an unincorporated community of Los Angeles County. The County states that in unincorporated areas, services such as law enforcement, firefighting, road maintenance and parks are provided by the County rather than a city, and residents are represented by the Board of Supervisors (Los Angeles County, 2026).
What school districts serve Castaic?
Two. Castaic Union School District covers kindergarten through grade 8 with five schools and 1,914 students in 2024-25, and the William S. Hart Union High School District covers grades 9 through 12, including Castaic High with 1,159 students (NCES, 2024-25). Confirm your address with each district.
Does Castaic have Mello-Roos taxes?
Some tracts do, and amounts vary by parcel. California Civil Code Section 1102.6b requires the seller to make a good faith effort to obtain and deliver a disclosure notice covering any Mello-Roos special tax or 1915 Act assessment (California Legislative Information, 2026). Request that notice before removing contingencies.
How busy is the I-5 through Castaic?
Caltrans measured roughly 71,000 vehicles a day on I-5 just south of Lake Hughes Road in 2024, compared with 171,000 south of Valencia Boulevard and 194,000 near Calgrove Boulevard (Caltrans, 2024). Castaic sits on the lightest-volume valley stretch, with volume building at every interchange southbound.
Can you use Castaic Lake for recreation?
Yes, through the Los Angeles County-run Castaic Lake State Recreation Area. The county lists vehicle entry at $15.00 daily, boating at $9.00 non-motorized and $13.00 motorized, regional parks closed Mondays and Tuesdays, and campgrounds closed after Hughes fire damage (LA County Parks, 2026). Check current conditions before planning.
The short version
Castaic gives you county services instead of city services, a K-8 elementary district that hands off to the Hart district at grade 9, the lightest traffic volumes on the valley’s stretch of I-5, and a reservoir that sat at 94% of capacity in early September 2026.
Verify in this order: confirm school assignment with the district, pull the tax bill and any special assessment notice, then drive the commute from the on-ramp you’d actually use, at the hour you’d actually leave. If you’d like help doing that for a specific address, reach out through the contact page.
