How does the Mills Act lower property taxes on a historic Riverside home?

The Mills Act is a state law that lets the City of Riverside contract with the owner of a qualified historic home to change how the county assessor values that property for tax purposes, in exchange for the owner committing to restore and maintain it. It is not a discount you apply for at the tax office. It is a recorded contract between you and the city, and it changes the math the assessor uses every year the contract is in place.

Riverside has one of the older, more active historic preservation programs in the Inland Empire, going back more than thirty years, and the state’s Office of Historic Preservation has certified the city’s program as meeting state and federal standards. If you own, or are buying, a designated historic home here, the Mills Act is worth understanding before you assume your tax bill works like every other house on the block.

Which Riverside homes qualify, and when to apply

A property has to already carry some form of historic designation before the Mills Act comes into play. In Riverside that generally means the home is a designated landmark or structure of merit, or a contributing structure within one of the city’s historic districts, such as Heritage Square, Mt. Rubidoux, North Hill, or Palm Heights. State law defines a qualifying property more broadly, as one listed in the National Register of Historic Places or in a registered historic district, or listed on a state, city, or county official register of historically or architecturally significant sites. If a home has never been through that designation process, there is nothing yet for a Mills Act contract to attach to.

The city accepts Mills Act applications once a year, from January 1 through May 31, with the application packet posted on the Planning Division’s forms page. That window can close on the last business day of May rather than the calendar date itself, so if you are thinking about applying, confirm the exact deadline on the city’s Historic Preservation page before you assume you have until the end of the month.

What the owner commits to

Signing a Mills Act contract is not a one-time favor to your tax bill. Under state law, the contract runs for a minimum of ten years, and it renews automatically by one year on each anniversary unless either side gives notice of nonrenewal, which means in practice it can run indefinitely as long as neither party opts out. The owner agrees to preserve the property and, where necessary, restore and rehabilitate it to standards drawn from the Secretary of the Interior’s Standards for Rehabilitation and the State Historical Building Code, and Riverside layers its own Certificate of Appropriateness review and district design guidelines on top of that for exterior changes.

The city inspects the interior and exterior before a new contract is signed, and again every five years after that, to confirm the owner is holding up their end. If an owner lets the property deteriorate below the standard for a qualified historical property, or otherwise breaks the contract, the city can go to court to enforce it or move to cancel it. This is a real, monitored obligation, not paperwork you file and forget. And any restoration work still has to be permitted the normal way. Skipping that step to save time just creates an unpermitted work problem on top of a historic property compliance problem.

How the tax reduction actually works

This is where a lot of confusion comes in, so it is worth being direct about it. The Mills Act does not just shave a fixed rate off your existing bill. It changes the method the county assessor uses to value the property in the first place. Under Revenue and Taxation Code sections 439 through 439.4, a restricted historical property is valued using the capitalization of income method rather than the standard market approach that looks at comparable sales.

In plain terms, the assessor estimates what the property could reasonably rent for, subtracts the ordinary costs of operating it, and divides that net income by a capitalization rate built from current mortgage interest rates plus a few fixed components set in state law. That number becomes the assessed value the tax rate applies to, instead of a figure tied to what similar homes are selling for. Because rents and mortgage rates vary by year and by neighborhood, the result varies too. For an older home in a desirable historic district with rising market values, this often produces a meaningful reduction from what the standard approach would show. It is not guaranteed, and it is not a fixed number, so treat any specific dollar figure someone quotes you as an estimate to verify with the assessor’s office, not a promise.

This is a different mechanism from a Prop 19 base year value transfer, which lets an eligible older or disabled homeowner carry an existing low tax base to a new home. A Mills Act contract does not move a tax base anywhere. It changes how this specific property gets valued, year by year, for as long as the contract runs.

What happens when a Mills Act home is sold

A Mills Act contract is recorded against the property, and state law is specific that it binds all successors in interest the same way it bound the original owner. When the home sells, the buyer does not get to opt out of the restoration and maintenance obligations, and they inherit whatever years remain on the ten-year term. The city has to record a copy of the contract with the county recorder within twenty days of signing it, which is exactly what makes it show up in a title search later.

For a buyer, that cuts both ways. You may be buying into a lower assessed value that carries forward, which is attractive. You are also buying into the same restoration standards, periodic city inspections, and the same risk of a breach-of-contract cancellation if a future owner (possibly you) lets the property slide. Ask your agent or a real estate attorney to verify exactly how many years remain and what the contract specifically requires before you assume the numbers you were shown will hold.

How to check if a home already has a Mills Act contract

Because the contract has to be recorded with the county recorder, it should turn up in a standard title search or preliminary title report during escrow, the same way a lien or easement would. A buyer’s agent or escrow officer can also ask the seller directly, and a seller who knows should say so plainly rather than let it surface later. Riverside’s Planning Division and the county assessor’s office can both confirm whether a specific address carries an active contract, which is worth doing before you write an offer if a listing markets a home as historic without saying whether a Mills Act contract actually exists.

How to market it honestly, and how a contract ends

If you are selling a home under a Mills Act contract, say so plainly and describe what it actually is: a recorded restoration agreement that transfers to the buyer, not a one-time perk that stays with you. Do not promise a specific tax number. Point buyers to the county assessor’s office for a current estimate and let them verify the remaining contract term themselves. It also belongs in your disclosures. It is exactly the kind of known, recorded fact about the property that the seller disclosure guide covers, and a buyer should not be finding out about restoration obligations for the first time in the title report.

Contracts do not last forever by default, but ending one is not simple either. Either the owner or the city can serve notice of nonrenewal before the annual renewal date, after which the existing term winds down rather than resetting. If the city instead cancels the contract for a breach, state law requires a public hearing first, and the owner then owes a cancellation fee equal to one eighth of the property’s current fair market value, calculated as though the contract never existed. That fee is a real number worth knowing if you are weighing whether to keep the commitment going.

The short version

The Mills Act lets a Riverside owner of a qualified historic home trade a real, recorded restoration commitment for a different, often lower, property tax valuation based on income rather than market comparables. It runs with the land, so a buyer takes on the same obligations the seller had, for whatever years are left. Verify an active contract through the title report or the city and assessor directly, and treat any savings figure as an estimate until the assessor confirms it.

If you are buying or selling a historic home in Riverside and want the tax picture and everything else laid out clearly before you commit, start with the home value tool. It is a starting point before a conversation about your specific home.