How much sales tax do San Mateo County residents pay — or want to pay?

The new revenue measures this year, however, are mostly going toward maintaining basic services or, according to transit agencies, preventing catastrophic collapse.

Breaking down the county’s sales taxes

San Mateo County has a 9.375% minimum sales tax rate — the fifth-highest among the state’s 58 counties — though most jurisdictions are higher after incorporating city-specific measures.

California imposes a 6% sales tax for state-level needs and an additional 1.25% for local agencies — 1% of that going to city and county operations and 0.25% to county transportation funds.

On top of that, the county administers five sales taxes of its own. Four of those — Measures A, W, RR and the San Mateo County Transit District tax — are dedicated to transportation, including road repairs, bike infrastructure, highway projects and public transit agencies like Caltrain and SamTrans.

The fifth sales tax, Measure K, goes to a variety of services, ranging from affordable housing to emergency operations and healthcare.

Most cities in the county have at least a 9.625% rate, with a handful — including Belmont, Redwood City, San Bruno, Half Moon Bay and South San Francisco — at 9.875%.

Sales tax limits

Technically, the state allows local jurisdictions to add on no more than 2% to the 7.25% rate — a combined 9.25% limit — but many counties, including San Mateo, exceed that.

“Up to 2% is the starting place of the law, but in many locations, when they are bumping up against that 9.25%, an agency goes to the state and asks for its rate to be exempt,” said Michael Coleman, a municipal finance expert.

In May, the San Mateo County Board of Supervisors voted 3-2 to support legislation allowing another sales tax limit increase.

Sales taxes to come

This November, voters will decide whether to add one — in some cases, two — more sales taxes and perhaps another in 2028.

The Connect Bay Area initiative, which just officially qualified for the ballot, would be the sixth transit-related sales tax in the county — in addition to the four county-administered measures plus the 0.25% portion from the state tax — and would largely bridge the gaping deficits of most major transit agencies, including Caltrain and BART.

Cities like San Mateo and San Carlos seem poised to add an additional sales tax to their ballots as well. Some county leaders have discussed adding another sales tax in the near future and will most likely ask voters to extend Measure A again in 2028.

Regressive but easy to pass

Unlike other types of taxes, such as income or property, sales taxes are often considered the most regressive, as they don’t take into account residents’ socioeconomic status. At the same time, they're often the easiest types of revenue measures to pass since they’re often general purpose and therefore just need a simple majority, rather than a two-thirds threshold, to pass. For the regional transit measure, some leaders, like Jackie Speier, San Mateo County supervisor and San Mateo County Transportation Authority board member, pushed for a gross receipts tax on businesses instead of a sales tax, however, that was vehemently opposed by some groups like the Bay Area Council.

“Our first choice was not a sales tax, and we preferred other forms of less regressive taxation," said Adina Levin, executive director of Seamless Bay Area, but added that it was the only way for all regional agencies to get on board.

More skepticism with higher costs

Many Peninsula jurisdictions are getting dangerously close to hitting their sales tax thresholds, prompting city leaders to act quickly to get a local measure on their ballots before another agency beats them to it.

“If we don't ask voters now for the opportunity to use that capacity toward local services, we may lose that opportunity to ask in the future,” San Mateo Mayor Adam Loraine said of the city's possible measure.

San Mateo County Supervisor Ray Mueller said another transit-dedicated tax cuts into city and county revenue opportunities.

“Whenever there is one agency that is taxing in excess, it takes away the voter goodwill,” Mueller said.

Even though the transit measure is technically exempt from the legal threshold, repeatedly asking voters for more money affects public trust and their decisions for future initiatives, he said.

“There is some level of tax support they get but they can’t keep increasing that level of tax support such that they hurt the rest of the economy and the rest of the businesses,” Mueller said. “Some of the money from this measure will go to agencies with surpluses and also agencies that don't even serve [some taxpayers].”

While Caltrain and BART are facing $75 million and $376 million average annual deficits, respectively, SamTrans — Caltrain’s managing agency — projected a $13 million operating surplus for the 2025-26 fiscal year.

As inflation remains stubbornly high and affordability remains a key voting issue, the sentiment toward raising taxes isn’t getting any rosier.

“According to our latest poll, if [voters] had to make a choice, they’d prefer lower taxes and fewer services for the state government, and in a lot of circumstances that will apply to local governments as well,” said Michael Baldassare, survey director at the Public Policy Institute of California.

Messaging in favor of the new taxes is often uninspiring, as the revenue will only go toward maintaining basic operations and in some cases, preventing abrupt closures.

“Just saying, ‘it's to keep our heads above water’ may not be enough,” Baldassare said.

For Jim Lawrence, a Foster City resident and former mayor, more sales taxes represent an inability for agencies and governments to live within their means.

“There are people with fixed incomes, seniors living on Social Security, and they keep increasing our [costs],” Lawrence said.

Optimistic on investment

Still, a recent poll showed that a majority of San Mateo voters are likely to support another city sales tax. Locally-focused measures are often most successful, as residents feel the funds will more directly benefit them.

“In our recent polling, 80% mentioned that the city’s services are satisfying, that we appear to be doing a good job and meeting needs,” Loraine said. “We just happen to have costs increasing at this time and economic uncertainty, with state and federal funds that will imperil our ability to provide that level of service without some other revenue measure.”

And for transit riders, the cost of a half-cent sales tax is still cheaper than the extra rideshare costs if service is cut.

“This tax would maybe be $5 to $10 a month, and if you have to take an Uber or Lyft just once because your train isn't running, you have more than covered your costs,” Levin said. “Looking at the big picture, in places around the world where the transit is really good … those regions and countries put in a lot more public funding than we do into their transit system.”

Incorporating the statewide ballot

The statewide ballot measures seem to reflect the combination of voter skepticism and uncertainty over how to deal with intensifying budget pressures at the government level while their own finances are getting squeezed.

For instance, the billionaire tax — which levies a one-time 5% tax on those with a net worth of at least $1 billion in assets — could be more appealing to voters who feel they’re already stretched thin, Baldassare said.

“It speaks to general sentiment that the wealthy should pay more,” he said. “They may see [other measures] and say, ‘it should be someone else, not me.’”

There are also several other statewide measures meant to limit higher taxes and increase accountability. One of them would require audits for certain ballot initiatives that impose special taxes and another would prohibit new personal property taxes and limit retroactive taxes. A third one would require a two-thirds majority to pass local taxes that qualify via signature-gathering methods.

“There is a belief that governments could be more efficient in how they spend money … so unless there is some emergency where police or fire services are going to be affected, there may be more reluctance to say yes,” Baldassare said.