Coronado homeowners with properties at least 75 years old may qualify for property tax cuts of 20 to 70 percent under a little-publicized state program.
The savings come through the Mills Act, a California law that rewards owners who maintain the historic character of their homes. Coronado has about 200 properties enrolled, generating a combined $3.4 million in tax savings during the 2025–2026 tax year, the San Diego Union-Tribune reported in March.
The biggest local beneficiary: Crown Manor at 1015 Ocean Blvd., a Tudor-style estate built in 1902 and designed by architects William Sterling Hebbard and Irving Gill. Its owners saved $166,081 in the 2025–2026 tax year. Coronado Castle at 1127 F Ave., a 1924 Richard Requa-designed Mission Revival home, saved $127,744. A third Requa property at 1045 Loma Ave. saved $120,858.
The tax breaks add up fast. Countywide, Mills Act participants saved an estimated $29 million in the 2025–2026 tax year, with an average discount of 71 percent, according to the Union-Tribune's analysis of assessor data.
What qualifies
Under Coronado Municipal Code Chapter 84.10, a property may earn historic designation from the city's Historic Resource Commission if it is at least 75 years old, or has achieved historic significance within the past 75 years, and meets two or more additional criteria, the Coronado Times reported in a Sept. 14 explainer by Kimberly Ussery. Those criteria include reflecting Coronado's military, cultural or architectural history; being tied to a significant person or event; retaining distinctive architectural features; or representing the notable work of a recognized architect or builder.
Architects on the city's historic register include Irving Gill, William Templeton Johnson and Richard Requa.
What historic designation controls
A common misconception is that historic designation locks owners out of changes. The program regulates only the exterior, according to the Coronado Times. Interior remodeling is unrestricted unless it affects the outside appearance.
Exterior modifications are allowed but must first be approved by the Historic Resource Commission. Owners also gain exceptions to some zoning standards, access to the California State Historic Building Code and reduced permitting fees.
Accessory dwelling units are permitted on historic properties as long as the new structure does not affect the public-facing facade. Under Coronado Municipal Code Chapter 86.56.105, owners can also convert existing carriage houses into ADUs by adding kitchens and bathrooms.
The city does not require a historic-significance review during real estate transactions.
How the contract works
A Mills Act contract runs a minimum of 10 years and renews automatically each year. The contract stays with the property, not the owner. When a home sells, the new buyer inherits the agreement and the tax benefit.
In return, owners must maintain the property according to the Secretary of the Interior's Standards for the Treatment of Historic Properties. The city may inspect periodically to ensure compliance.
Jim Newland, historian at the La Mesa History Center, told the Coronado Times that qualifying properties typically save about 60 percent on property taxes. The California Office of Historic Preservation has called the Mills Act the single most important economic incentive for restoring and preserving qualified historic buildings in California.
A Coronado origin story
The law has local roots. Former state Sen. James Mills, who represented San Diego County, authored the legislation in 1972 after a developer proposed demolishing the Hotel del Coronado, according to Wikipedia. The law was struck down as unconstitutional in 1973, but California voters approved it as a constitutional amendment in 1976.
Christine Stokes, executive director of the Coronado Historical Association, captured the preservation ethos at the CHA's GEM awards dinner in April 2024: "The purpose of the GEM is that someone is going the extra mile to preserve a potential teardown."
Applications and resources are available on the city's preservation page. The city also maintains a list of properties determined to be non-historic; homes on that list do not qualify.
