Blog Our Future is Better with Multiplexes

April 4, 2023

We’re excited to see a growing movement in Bay Area communities to remove restrictive zoning and re-enable multi-unit development — like multiplexes! — in our neighborhoods.  Towns across the Bay Area, from Berkeley to the Peninsula, are re-examining their zoning codes to consider allowing duplexes, triplexes, and quads to be built on existing lots that are currently limited to just one home.  In many cases, this allows neighborhoods to again build the kinds of multi-unit homes that are already there — blending right in!

Fourplexes tweet

Read on for more about how our suburbs started, how they’re going, and how returning to our roots (when plexes were plentiful!) will help us address our current crises.

Plexes: The History

Visit older sections of any major city, and notice how the homes were built in the early 20th century.  On first glance, it may be hard to tell that many of the buildings are actually multi-plexes!  These neighborhoods often have “stealthy density” already built in.  Many were built around old rail lines that have since been replaced by buses, and some of the homes have no parking at all.  Many of the older multi-unit buildings would also be illegal to build today under current zoning codes, which in many places only allow a maximum of one unit per lot.

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While some residents may prefer the luxury of single family homes and are welcome to continue doing so under expanded zoning, others may prefer to live in community with others to share maintenance and costs, or to enable intergenerational living — another “old” concept that’s more appealing than ever as Millennials, now well into their 30s, sort out how to work and care for children and their own parents at the same time.

What does our future look like with plexes?  They provide us with:

More options:

One great thing about opening up restrictive zoning is that it provides property owners with more choices what to do with their land, not fewer:

  • A young family may choose to build another unit on their lot for easy access to aging parents, or housing for another friend or family member to share costs
  • Families with young adult children could add another unit for the child to live in as they get started in the workforce
  • Retirees could add a unit or redevelop their home to provide rental income in retirement
  • Friends could pool their resources to build and co-own a multi-unit building or share a plot of land
  • A family who inherits a family home could redevelop the property so that more members of the family can live there, instead of having to sell it off
  • Builders can repurpose dilapidated old homes into thriving multi-unit buildings so more members of the community can live close to work.  Under current single-family zoning, developers are forced to develop only single-unit multi-million dollar mansions, as no alternative options exist.

Saner and greener commutes:

Below is a map showing the growth in “supercommuters” — those who commute more than 90 minutes each way — between 2009 and 2017:

Map of “supercommuters” in the Bay Area. Source:

With so much Peninsula housing stock currently occupied by retirees (some of whom feel trapped in place by their Prop 13 property tax subsidies) and a severe lack of new building, those who actively participate in the workforce are forced further and further away.  This endangers quality of life for us all, even those who live on the Peninsula; our shops, services, and communities are understaffed and must pay more to incent staff to travel in from far away.  These longer travel times also cause traffic and pollution in our region due to the lack of public transit available to “supercommuters.”

Although a unit of housing — even affordable housing — can cost $1m to build here in California due to our byzantine, lengthy approvals process (see Firehouse Square in Belmont which took almost a decade to approve on a site that sat vacant for 20 years), moving to a “by right” approval model (where projects that comply with zoning are automatically approved) and allowing height/density increases will ease per-unit costs of construction, allowing these units to again become more attainable for typical Bay Area workers and families.

More equity:

The current average rent for a 2-bedroom apartment in the town of San Mateo is $2,942, according to Zumper.  With minimum wages around $15 in most cities in the county, it would take about 50 hours of work per week, before taxes, to simply cover monthly rent.  

Studies show that as new units of housing are added — even if those units are market rate supply and demand works, with existing (older) housing stock becoming more affordable as a result.  More affordable homes mean that those who work here can live here, too.  Workers and families of all types, races, and lifestyles are a critical part of our complete communities.

More resources

When a city’s housing base is stale, so is its tax revenue, due to 1978’s passage of Proposition 13 which generally pegs homeowners’ assessed values to the price at which the home was purchased.

Because of Prop 13 subsidies (which apply to residential and commercial properties alike) and the lack of new development in our region, our state and local governments have simultaneously been forced to raise other forms of taxation and cut services (such as tuition-free college for in-state students and school buses for local schoolchildren).  Prop 13 was passed in 1978.  Cities in 2021 cannot run on 1970s-era revenue.

New housing brings not only the direct tax revenue created by the development itself, but also provides new residents who can support local businesses, improving the community for all.  Imagine what additional retail, services, and restaurants we could support here as ground floor retail in new developments if we had more residents to support these businesses.  Paris Mayor Anne Hidalgo has championed The 15 Minute City movement, focused on walkable communities similar to those that exist in many Parisian neighborhoods.  Imagine how well the European model could work in our existing downtowns and neighborhood enclaves, which today require residents to get in a car to meet their daily needs.

In summary

With economic, social, and equity benefits on the horizon, our future with plexes looks bright.  Infill development allows middle class residents — just like those who purchased homes here decades ago — to live in the communities where they work.  And as economically and racially diverse communities grow and thrive, existing homeowners’ land becomes more valuable as the possibilities for what can be built there expand.  Expanding zoning is a wonderful policy change that benefits all stakeholders in the community!

Ready to take action?

Evolving the zoning in our local communities is an ongoing process, and the more voices in support, the better.  Join us in raising awareness about the benefits of multiplexes in our communities:

  • There’s a great statewide bill up for a vote soon here in California called SB-9 that would enable infill housing to be built in existing neighborhoods.  Use this tool to drop a quick line to your State Senator in support.
  • Many Bay Area city councils are also separately (independently from SB-9) beginning to explore changing city zoning to allow multiplexes in light of our housing crisis.  Get in touch with your local electeds however you prefer — email, phone, social media — and let them know that you support more inclusive housing.
  • Sign up for our email list and follow us on social media (Twitter, Facebook, Instagram) for the latest updates on multiplexes in our area!