"The Mills Act was set up to help you restore the houses. In San Diego, you pretty much have to be restored before you can get the Mills Act," Bruce Coons, executive director of Save Our Heritage Organisation, told the San Diego Union-Tribune in March 2026. Coons was criticizing the way San Diego makes owners pay for restoration before they get any tax relief. For a North Park seller, the same fact has another side. The owner who did the restoration paid for it. The owner who buys the house afterward inherits the contract, the restored porch columns and, in many cases, a larger tax discount than the seller ever got.
That is how the program is built. The size of the break depends far more on when you bought the house than on how much you spent restoring it.
The tax bill follows the rent, and the rent ignores the sale price
Most California homeowners know the Prop 13 rule. A sale resets the assessed value to the purchase price. A Mills Act property goes through that reset too. Board of Equalization guidance tells assessors that when a contracted property changes hands, "a new base year value should be established for the property as of the date of change in ownership." Then the assessor compares three numbers every year and enrolls the lowest one.
| Value the assessor compares | What sets it |
|---|---|
| Factored base year value | The value at the most recent change in ownership, adjusted each year by the inflation factor |
| Current market value | What the property would sell for on the lien date |
| Restricted value | Fair rent for the property, minus allowed expenses, divided by a prescribed capitalization rate |
The restricted value is the one that matters. The BOE says fair rent should account for actual and comparable rents for similar properties in similar use. Allowed expenses include maintenance, repairs, insurance, utilities and management. For an owner-occupied single-family home, the guideline adds a 4% risk component to the capitalization rate. The purchase price does not enter the restricted value calculation. A buyer can pay any amount for a Craftsman on a Burlingame street, and the restricted value is still based on what the house would rent for. The price still sets the buyer's new base year value, which stays in the three-way comparison.
The BOE expects this to favor the buyer. Its guidance says a restricted property's new base year value "typically" exceeds its restricted value and "hence will not be enrolled." When that typical case holds, the new owner's taxes are calculated from rent, and the higher price they just paid is set aside.
Why a long-time owner often captured less of it
Run the same three-way comparison for someone who bought decades ago. Their factored base year value may already be low. If it falls below the restricted value, that low base is what gets enrolled, and the Mills Act adds little. City officials made the same point to the Union-Tribune. They said some families who have owned their homes for generations pay low enough taxes that they would not save much with the Mills Act.
The buyer is in the opposite position. Their Prop 13 base is reset to today's price, so the gap between that base and the rent-based value is as wide as it can be. Countywide, the Union-Tribune found an average 71% property tax discount among participants. It also estimated that owners in the city of San Diego saved an estimated $23.6 million in property taxes in the year of its March 2026 analysis, across more than 1,900 contracts. North Park is one of the neighborhoods where those contracts cluster, along with South Park, Mission Hills and La Jolla.
Some owners have already acted on this. The Union-Tribune reported that some homeowners apply even when they will get no tax discount, because the designation helps the home's value when they sell. When the benefit goes mainly to the next owner, it shows up in the sale, not in the seller's annual tax bill.
What the buyer inherits along with the discount
A buyer who values the tax break will also want to know what comes with it. That list is the seller's disclosure conversation, and it shapes the renovation scope. The City's FAQ says Mills Act benefits "go with the land," so new owners "inherit" both the benefits and the responsibilities without applying again. State law binds "all successors in interest" to the same rights and obligations as the original owner. It also requires the contract to be recorded with the county recorder, which serves as public notice.
The obligations that carry over:
- Maintenance to the Secretary of the Interior's Standards, plus a 10-year maintenance and rehabilitation work plan.
- Monitoring every five years, with a fee of $893.67 under the City fee schedule updated July 1, 2025. The City says monitoring lets staff contact a new owner after a sale and explain what the contract requires.
- A rolling 10-year term. Each year the agreement renews so that 10 years remain. If either party serves notice to stop renewal, the agreement runs until its current expiration date, about ten years after the notice is recorded.
- A cancellation penalty for breach. If the City cancels the contract after notice and a public hearing, state law imposes a fee of 12.5% of the property's current fair market value, valued as if the contract did not exist.
Item three matters to a seller. Once a nonrenewal notice is served, BOE guidance tells assessors to phase the value up from the restricted value toward the applicable base year value. A contract in nonrenewal gives a buyer a shrinking discount. A seller who filed nonrenewal before deciding to list has already given up part of what made the house attractive to buyers.
Item four is why the renovation scope matters. A 12.5% penalty is a large number to put at risk with a careless exterior update.
Where pre-sale renovation runs into review
North Park's designated districts include Shirley Ann Place, designated in 2000, Burlingame, first designated in 2002 and converted to a geographic district in 2007, and North Park Dryden, which the North Park Historical Society reports was designated in 2011. The City lists Valle Vista Terrace, with 90 properties, as designated in November 2017 and Melhorn & Son in October 2018. SOHO wrote in its May/June 2026 newsletter that the City has approved no local district since 2017. The City's own page lists the 2018 designation, so the two sources disagree. Park Boulevard, Altadena and Kalmia Place are listed as in process.
Inside an adopted district, the City requires owners to get approval for maintenance, restoration or alteration "prior to purchasing materials or undertaking work." The City also says historic review runs concurrently with other permit approvals. Outside a district, most older North Park homes still face the City's Potential Historical Resource Review. In February 2025, City staff said that review reached buildings constructed before 1981. Under Information Bulletin 580, it applies to construction permits, including No-Plan permits, that affect a structure 45 years old or older.
How a typical pre-sale scope splits:
- Interior work, and electrical, plumbing or mechanical work with no exterior change, is exempt from the 45-year review. That covers kitchens, baths, flooring and paint, where most of a renovate-to-list budget goes.
- Permitted exterior work such as windows, porches, roofing and additions triggers the review. The typical timeline is about 10 business days for ministerial projects and 20 for discretionary ones.
- If staff finds a property potentially historic, the project is reviewed against the Secretary of the Interior's Standards. It may require a Historical Research Report and a designation hearing before the Historical Resources Board. If staff finds the property not historic, it is exempt from further historic review for five years.
These reviews are routine in North Park. The North Park Historical Society's summary of its 2024 work reports that one contributor reviewed 141 City permit applications for buildings over 45 years old, 87 of them for ADUs, and weighed whether a full historical report should be required.
A homeowner with a Mills Act contract told the Union-Tribune they had spent about $250,000 on renovations, some of them made to comply with the contract. They replaced the roof, scraped and repainted windows, redid the paving out front and restored two porch columns. For a seller, that kind of exterior work keeps a contract in good standing. A vinyl window swap is the kind of shortcut that can put it at risk.
The rules a sale this season will close under
The City is rewriting this system, but the rewrite is not in effect. Package A of the Preservation and Progress update was approved on February 24, 2026. It added a new ground for appealing a historic designation and left the 45-year review alone. Package B is the part that would change the Mills Act and move the 45-year review toward "proactive preservation that protects important resources and districts." In April 2026, a City spokesperson told Times of San Diego that Package B was still being prepared and that Council approval was anticipated in early 2027. The City Planning Department's later update also places it before the Land Use and Housing Committee and Council in 2027. A listing that opens this fall or winter will be reviewed under the current Information Bulletin 580, which is still dated October 2020, and the current Mills Act terms.
Questions sellers ask
Does my buyer have to apply for the Mills Act? No. Per the City FAQ, the recorded agreement transfers and the new owner inherits it.
Is the buyer guaranteed the discount? No. The Office of Historic Preservation says the assessor enrolls the lowest of the three values every year, and Mills Act values are recalculated annually. The County Assessor can confirm how this applies to a specific parcel, and that applies to your own figures too. Nothing here is tax or legal advice.
Could my home get designated after I list it? A permitted exterior project on a pre-1981 home can lead to a historic evaluation. Planning that work early avoids surprises in escrow.
What does a Mills Act application cost if my home is not yet enrolled? The Union-Tribune reported a $3,444 fee for local designation and $1,334 for the Mills Act application. Research reports often run more than 100 pages, and consultants to prepare them can cost $10,000 or more.
If you are selling a North Park home with a recorded Mills Act contract or a historic district designation, Renovation Realty can scope the interior updates that skip historic review, plan any exterior work so it meets the Secretary of the Interior's Standards, and defer the renovation cost until close of escrow. Book a Free Home Evaluation, and we will walk through your contract's obligations before anyone buys materials.
