Two fourplexes sit four blocks apart in Mountain View, both built in the 1970s, both with the same unit mix, both listed within a few thousand dollars of each other per door. An investor comparing them on price per unit would call it a coin flip. It isn't. One building can raise rent by a fixed, CPI-tied percentage each year and nothing more. The other can reset every unit to whatever the market will bear the moment a tenant moves out. The difference has nothing to do with the neighborhood, the finishes, or the seller's asking price. It comes down to a single date stamped on the certificate of occupancy: February 1, 1995.

That date is the hinge of Mountain View's Community Stabilization and Fair Rent Act, known locally as the CSFRA, and it is the piece of due diligence that separates buyers who underwrite correctly from buyers who find out the hard way after closing.

Why the Construction Date Outweighs the Comps

Mountain View voters passed the CSFRA as Measure V in November 2016, and the city's Rental Housing Committee has administered it ever since. The ordinance sorts rental property into three distinct buckets, and each one behaves like a different asset class when you run the numbers.

Multi-family buildings with three or more units built on or before February 1, 1995 are fully covered. That means both a capped annual rent increase and just-cause eviction protections apply. Buildings with three or more units constructed between February 1, 1995 and December 23, 2016 are partially covered. There is no rent cap on these, but the just-cause eviction rules still apply, so a landlord can charge market rent but still needs a lawful reason to end a tenancy. Single-family homes and condos are exempt from the CSFRA's rent cap entirely under the state's Costa-Hawkins Rental Housing Act, though CSFRA's eviction rules can still touch broader unit types depending on circumstance.

For the current period, that Annual General Adjustment is 2.7 percent, effective September 1, 2025 through August 31, 2026. The Rental Housing Committee set the figure by resolution on April 24, 2025, calculating it as 100 percent of the change in the Bay Area's Consumer Price Index, measured February to February, with the ordinance requiring a floor of 2 percent and a ceiling of 5 percent no matter which way inflation moves. A separate, lower adjustment of 1.6 percent applies to mobile home spaces under the city's parallel Mobile Home Rent Stabilization Ordinance, calculated on a different formula entirely.

Run that 2.7 percent against a fourplex where every unit has a long-tenured tenant and you get a rent roll that grows slower than inflation in a market where Google, LinkedIn, and the surrounding tech employment base keep pushing asking rents upward every year. Run the same 2.7 percent against a partially covered building from 2004 and it means nothing, because that building was never capped to begin with.

The Turnover Clause Most Buyers Miss

Here is the part of the ordinance that changes how a smart investor reads a rent roll. Fully covered units are subject to vacancy decontrol. When a tenant in a covered unit moves out, the landlord can reset that unit's rent to market rate for the incoming tenant. Once the new tenancy begins, the unit falls back under CSFRA's annual cap, but the reset itself is not limited.

That single mechanic flips the usual investor instinct upside down. In most markets, long-term tenants paying below-market rent look like a problem to be managed. In a fully covered Mountain View building, a below-market legacy tenant is not dead weight. It is a rent roll that has years of upside sitting behind a lease, released the moment that tenant leaves voluntarily. The building's real cash-on-cash return depends less on today's trailing twelve months of income and more on how close the current tenants are to turning over. Two buildings with identical current rent rolls can have completely different five-year cash flow projections depending on tenant tenure alone, and that is not a line item most offering memos spell out.

This is also why modeling a fully covered acquisition off current market comps is a mistake. A lender or an agent who treats the trailing rent roll as a ceiling rather than a floor will misprice the deal in either direction.

The Paperwork That Trips Up First-Time Landlords

Beyond the cap itself, the CSFRA carries administrative obligations that catch new owners off guard, usually within the first year of ownership.

Every landlord of a CSFRA-covered unit must register the property with the Rental Housing Committee and pay an annual fee. For fiscal year 2025-26, the city set that fee at $130 per unit for CSFRA-covered properties, with a separate $142 per space fee under the mobile home ordinance. Both registration and payment are due January 31 each year, and the penalties for missing that date compound. Unpaid fees accrue a late charge of 4 percent per unit per month, and failing to register at all adds a separate $25 per unit per month charge, with both able to stack simultaneously. A landlord who falls substantially out of compliance cannot lawfully raise rent or file a petition for an increase, and the city posts noncompliant properties to a public, searchable database before escalation letters go out, first to the owner and then, if the situation persists, to the tenant directly.

Rent increases carry their own procedural requirements. A landlord can only implement the Annual General Adjustment once every twelve months, and must give the tenant thirty days' written notice before it takes effect. If an owner chooses not to take the full allowable increase in a given year, the unused portion can be banked and applied in combination with a future year's adjustment, according to the city's own program guidance. That banking option matters for an owner who inherits a below-market tenant at acquisition and wants to catch the rent up gradually rather than resetting it all at once through turnover.

Landlords who believe the standard adjustment does not cover their costs are not without recourse. The ordinance allows a landlord to petition the Rental Housing Committee for an upward adjustment based on a fair rate of return calculation or to pass through certain capital improvement costs, a formal process that runs through a hearing officer. Tenants have a parallel path to petition for a rent reduction if a landlord fails to maintain habitable conditions.

What This Means Before You Make an Offer

None of this changes whether Mountain View is a sound place to hold rental property. Proximity to major employers keeps rental demand persistent in a way that few markets can match. What it changes is how a buyer should read the offering memo before writing an offer.

The first question on any Mountain View multifamily deal should be the construction date, not the cap rate. That single fact determines whether you are buying an asset whose income grows at a CPI-bound pace or one that can be repriced to market at will. The second question is tenant tenure, because in a fully covered building that tenure is effectively an option on future rent growth. The third is compliance history, since an owner who has lapsed on registration or fees can hand a buyer someone else's penalty exposure along with the keys.

This is exactly the kind of detail that belongs in the financing conversation, not just the purchase agreement. A lender modeling debt service coverage on a fully covered building needs to underwrite against the capped rent trajectory, not a pro forma built on neighborhood comps. Getting that wrong in either direction, overstating the ceiling on a capped building or underpricing the upside in a building near full turnover, is how deals that looked solid on paper stop cash flowing in year two.

A Few Questions Worth Asking Before You Buy

Does the CSFRA cap apply if I buy the building and move into one unit myself? Owner-occupied situations still depend on the building's unit count and construction date under the ordinance. Confirm coverage status for your specific address and intended use with the Rental Housing Committee before assuming an owner-occupant exemption applies.

Can a new owner reset all the banked increases from a previous owner? The ability to apply a banked increase does not carry over to a new landlord following a change in ownership, according to the ordinance's structure, so a buyer should not assume they inherit a previous owner's unused adjustment history.

Is a single-family home a simpler investment because it avoids CSFRA entirely? Single-family homes and condos are exempt from the CSFRA rent cap under Costa-Hawkins, which does simplify the rent-increase math, but it does not eliminate every tenant protection question a landlord needs to research before signing a lease.

Mountain View's rental market rewards buyers who read the fine print before they read the rent roll. If you are weighing a multifamily purchase here, or trying to figure out how a CSFRA-covered property should actually be financed, Moles Group can walk through the numbers with you, from the Rental Housing Committee's coverage rules to what it means for your loan underwriting. Schedule a complimentary consultation and let's look at the specific address before you make an offer, not after.