The Cortese List is California’s consolidated inventory of properties with known or suspected hazardous substance problems, compiled under Government Code Section 65962.5 from databases maintained by four separate state agencies.1California Legislative Information. California Government Code 65962-5 If you are buying property, developing land, or checking what sits near a home or school, the list is where environmental due diligence starts. It is not a single document you can download or one search box you can type into. It is a set of agency datasets that the California Environmental Protection Agency (CalEPA) links together on one resource page, and you generally need to check more than one of them to see the full picture for a given address.
What’s Actually on the List
Four agencies feed the list, and each tracks a different kind of problem. Knowing which agency flagged a site tells you a lot about what the issue is.
Department of Toxic Substances Control
DTSC contributes the broadest set of records: hazardous waste facilities subject to corrective action orders under Health and Safety Code Section 25187.5, land formally designated as hazardous waste property, records of hazardous waste disposed on public land, and sites selected for state-led cleanup under Health and Safety Code Section 25356.1California Legislative Information. California Government Code 65962-5 The DTSC data also includes sites in the Abandoned Site Assessment Program, covering properties where the responsible party cannot be identified or has disappeared.2California Environmental Protection Agency. Cortese List Background and History
State Water Resources Control Board
The Water Board tracks underground storage tanks with unauthorized releases reported under Health and Safety Code Section 25295, solid waste disposal facilities where hazardous waste has migrated beyond the containment area, and cease-and-desist or cleanup orders issued after January 1, 1986, involving hazardous material discharges.1California Legislative Information. California Government Code 65962-5 Leaking underground storage tank sites alone account for thousands of entries, most involving fuel stations or industrial properties where aging tanks released petroleum into soil or groundwater.
Department of Health Services and CalRecycle
The Department of Health Services maintains a list of public drinking water wells where testing has detected organic contaminants.1California Legislative Information. California Government Code 65962-5 That matters most when a project relies on well water rather than municipal supply. Separately, local enforcement agencies compile lists of solid waste disposal facilities with known hazardous waste migration and submit them to the Department of Resources Recycling and Recovery (CalRecycle), which rolls them into one statewide dataset. These sites are often older landfills built before modern liner systems were standard.
How to Search the Cortese List
CalEPA’s Cortese List resource page is the hub. It links to each contributing database and, importantly, provides pre-filtered search links that return only the sites meeting Cortese List criteria rather than every record in the underlying system.3California Environmental Protection Agency. Cortese List Data Resources
EnviroStor
EnviroStor is DTSC’s data management system for hazardous waste sites and permitted facilities. You can search by address, city, zip code, or county using a map-based tool, and clicking a site opens its cleanup status, history, and available reports.4Department of Toxic Substances Control. How Can I Find Out if My Home, School, or Other Location Is Near a Hazardous Substances Site Use the Cortese-filtered EnviroStor link from CalEPA rather than a general EnviroStor search when you want to see only listed sites.3California Environmental Protection Agency. Cortese List Data Resources
GeoTracker
GeoTracker is the Water Board’s system, covering leaking underground storage tanks, cleanup program sites, and water quality data.5State Water Resources Control Board. Information in GeoTracker It offers the same map and address searching. CalEPA links to a GeoTracker search pre-filtered for leaking underground storage tank sites on the Cortese List, which saves you from sorting through unrelated monitoring data.3California Environmental Protection Agency. Cortese List Data Resources
Supplemental PDF Lists
Some Cortese List data is only published as PDFs, not searchable databases. CalEPA posts a list of solid waste disposal facilities with waste constituents above hazardous levels outside the containment area, a list of Site Cleanup Program sites, and a list of hazardous waste facilities subject to corrective action.3California Environmental Protection Agency. Cortese List Data Resources They are less convenient than the interactive databases, but they capture sites that may not surface in EnviroStor or GeoTracker searches.
What a Listing Means When You’re Buying
Finding a property on the Cortese List is a starting signal, not a verdict. The next step for any serious transaction is a Phase I Environmental Site Assessment conducted under ASTM International’s E1527-21 standard. A Phase I ESA constitutes “all appropriate inquiries” under CERCLA, which is the threshold a buyer must meet to qualify for federal landowner liability protections.6U.S. EPA. Brownfields All Appropriate Inquiries
A Phase I must be performed by a qualified environmental professional and includes interviews with current and past owners, review of historical records and government databases, a visual site inspection, and identification of “recognized environmental conditions.” The assessment has to be conducted or updated within one year before acquiring the property, and certain components such as interviews and on-site inspections must be completed within 180 days of acquisition.6U.S. EPA. Brownfields All Appropriate Inquiries A standard Phase I ESA typically costs between $1,500 and $5,000, though complex sites run higher. If it identifies possible contamination, a Phase II with subsurface sampling and lab work usually follows, and that is where costs climb quickly.
Financing is the other pressure point. Lenders treat contaminated properties as impaired collateral, because foreclosing on a contaminated site can make a lender an “owner” responsible for cleanup under CERCLA. In some jurisdictions, state or federal agencies can place environmental “super-priority liens” that take priority over existing mortgages. For SBA-backed loans, the SBA’s standard operating procedures require lenders to check whether underground storage tanks are present, whether prior investigations found contamination, and whether the property’s industry classification falls into an environmentally sensitive category. If contamination is confirmed, the lender must show the SBA that risks are “effectively managed,” which can mean a completed remediation or a No Further Action letter from the overseeing agency.
The liability net is wide. For hazardous waste facilities subject to corrective action, current and prior owners, lessees, operators, and anyone who produced, transported, or disposed of the waste can be held responsible for the state’s cleanup costs plus a 10 percent administrative surcharge (minimum $500).7California Legislative Information. California Health and Safety Code 25187-5 A buyer who skips the list and the Phase I can end up holding someone else’s cleanup bill.
What a Listing Means for Development Projects
The California Environmental Quality Act requires lead agencies to consult the Cortese List before approving a project. The standard CEQA Initial Study checklist asks directly whether a site appears on any list compiled under Government Code Section 65962.5 and, if so, whether it would create a significant hazard.
Public Resources Code Section 21092.6 places the primary burden on the lead agency, which must determine whether the project site or any alternatives appear on the compiled lists, specify which list, and include that information in environmental review documents including any negative declaration or draft Environmental Impact Report.8California Legislative Information. California Public Resources Code 21092-6 A listing does not automatically kill a project, but it does mean the review has to address what hazards exist and how they will be managed. That can push a project from a Negative Declaration into a full Environmental Impact Report, adding months and significant cost.
Developers carry their own obligation under Government Code Section 65962.5(f). Before a lead agency can accept a development application as complete, the applicant must consult the Cortese List and submit a signed “Hazardous Waste and Substances Statement” disclosing whether the property is listed.9California Legislative Information. California Government Code 65962-5 The statement has to name the specific list, the regulatory identification number, and the list date. If the site is listed but the applicant does not specify which list, the lead agency must notify the applicant of the incomplete application. Until the disclosure is right, the application never becomes complete and the review clock never starts.
Getting a Property Off the List
Properties do not stay listed forever if the contamination is addressed. The path off runs through the agency overseeing the site.
Owners who want DTSC oversight can apply for a voluntary agreement through the agency’s Request for Lead Agency Oversight process. After DTSC confirms it is the appropriate lead agency, the parties negotiate a site-specific agreement covering the scope of work, schedule, and oversight cost estimates. DTSC bills quarterly, and an advance payment is required when the agreement is signed. Buyers of contaminated sites can pursue a Prospective Purchaser Agreement, which releases the purchaser from environmental liability once the site is cleaned up under DTSC’s direction.10Department of Toxic Substances Control. Voluntary Agreements That tool is often what makes brownfield redevelopment feasible, because the new owner can take on the cleanup without inheriting open-ended liability from the prior contamination.
The goal of remediation is usually a No Further Action determination from the overseeing agency. Under CERCLA Section 128(b), completing cleanup through a state program can limit the EPA’s authority to pursue further enforcement or cost recovery against compliant parties. Read any NFA letter closely. It is typically based on conditions at the time of review and on the site’s intended use. If cleanup standards change, new information surfaces, or the land use shifts, the determination can be reopened. Some closures also depend on ongoing engineering or institutional controls to manage residual contamination that could not be fully removed. A site cleared for commercial use with a land-use restriction barring residential development is not cleared for housing, and anyone planning to build homes would need additional work before that use became possible.