Every Tuesday, the cerulean bus stops alongside the Main San Francisco public library. It stands there as a symbol of hope and possibility. And so much more. Run by Lava Mae, the bus is a mobile hygiene facility that is brought to the centers of San Francisco’s burgeoning homeless population. Six days a week, Lava Mae shower buses or trailers can be found at nine carefully located spots across the city. Above the windshield, where the travel destination information usually scrolls, are the words, “One shower at a time.”

Lava Mae is the brainchild of Doniece Sandoval. The former marketing dynamo moved to the Bay Area from her home state of Texas in mid-1990s. In 2012, she was tackling the important job of raising her adopted daughter when she walked by a homeless woman who was crying about her inability to get clean. The woman’s cries gave voice to a problem faced by San Francisco’s large homeless population. For the nearly 7,000 homeless people, half of whom live on the streets, there were only 16 shower stalls at eight locations in the city. Sandoval recognized her moment to act. She had been searching for a way to get involved in her adopted hometown. She thought about another distinctly San Francisco phenomenon: the vibrant food truck culture, and she had the inspiration to wonder if put-out-to-pasture MUNI buses could be retrofitted as shower buses, providing mobile hygiene services to the city’s struggling street denizens. “It’s impossible to live in San Francisco and not be impacted by homelessness,” she recalls. “For years I’d wanted to help but didn’t have a clue how to do that. I knew [that woman’s] words had many layers, but a light bulb went on in my head as I thought about how I might be able to help her get superficially clean.”

Four years later, there are two buses and one trailer, and more than 2,000 people have been able to take more than 14,000 showers. That Sandoval’s concept came to fruition is testament to her tenacity, sheer will, and special genius at distilling the concept of hygiene as a basic human right into a strong, marketable brand. John Rootenberg, chair of Lava Mae’s board of advisors, says, “She can have the effect of a bulldozer, but without seeming like one. She reminds me of the adage: ‘iron fist in a velvet glove’.”

For 18 months, Sandoval labored largely on her own, forging strategic alliances with city government and local social service agencies to ensure the fruition of her idea. She used her grit to wrangle a city bus for her pilot project, cut through endless bureaucracy to secure the necessary permits to restrict parking and secure the better part of a city block for the bus, hook up to the city hydrant, find a solution for gray water management, and secure a place to park the buses when not in use. And she used her eye for design and branding as she partnered with architects to create a welcoming, aesthetically pleasing, and powerful symbol of hope for the city’s homeless.

The first “bus” hit the road in June 2014. In September 2015, a second converted bus was added to the rotation, and in the spring of 2016, Lava Mae piloted a trailer.

Perhaps part of the brilliance of Lava Mae is that it doesn’t suggest that providing mobile showers and loos will cure homelessness on its own. Sandoval understands that Lava Mae’s buses and trailers are symbols of what is possible when you treat another human being with dignity. She and her team are fierce evangelists of what they call “radical hospitality.” “Lava Mae is breaking down the barrier of otherness,” comments Kathryn Doyle, with Draper Richards Kaplan. “It’s really changing perceptions because Lava Mae offers something so simple and tangible, and direct—you need a shower.”

Justin Steele, who oversees Google’s Bay Area Impact Challenge, which gave Lava Mae $100,000 in 2014, views the bus as a platform that is allowing Lava Mae to “build a sense of community and trust.”

That trust is engendered from the moment Lava Mae first makes contact with its guests, as it calls the people it serves. Two Lava Mae staffers are always on-site, aided by a number of dedicated volunteers. Those desiring a shower arrive to make a reservation with a Lava Mae ambassador for a shower at a specific time, lessening the need for mind-numbing queue lengths. Each bus is fitted with two showers and toilets (the trailer has three), and they are entirely private. For 15 minutes, Lava Mae’s guests are treated to the most privacy they’re likely to encounter during any given week. They are given a bag of toiletries (solicited and packaged—with a note—by numerous corporate volunteer teams), and with it, their dignity. Volunteers and staff further enhance their experience by acting as ambassadors of hospitality for their distinguished guests and by thoroughly cleaning the stalls between each visit.

Sandoval is quick to point out that collaboration with both the city government and local community service organizations has been central to Lava Mae’s ability to deliver services, as has the involvement of an active and engaged board and a dedicated corps of volunteers. At each street location, Lava Mae partners with a local non-profit that is working with the homeless. This arrangement means that Lava Mae’s guests are already proximate and don’t have to travel far for their shower and private toilet. It also allows the social service agencies and Lava Mae to work together to plug gaps in services.

The way they connect and work with each other is evolving as Lava Mae finds its sea legs. In April, Lava Mae coordinated the inaugural Pop-up Care Village at San Francisco’s Civic Center, to reduce the strain on people accessing various services. More than 250 homeless and at-risk housed people filled out index cards to sign up for up to three different services that were available right there: from hair cuts, to donated clothing, to medical and legal help. HandUp (2015 In Harmony with Hope Award winner) was one of the participating service organizations.

As the participants left, they turned their cards in. Leah Filler, who like many of Lava Mae’s 11 staff members, volunteered for the organization before she began working there as a founding member, serves as Lava Mae’s global community engagement director. She will use the information on those cards to learn which services were most requested. The cards will also form the start of a longer-term tracking system. Currently, Lava Mae might refer a guest to a particular service organization, but it has not had the ability to track them over time. Lava Mae’s plan is to have Pop-up Care Villages in different sections of the city every month to ease access to the full range of services Lava Mae’s guests need.

The Lava Mae brand has sparked the public’s imagination, generating inquiries from around the globe. Sandoval and her crew are taking a thoughtful approach to scaling. First, they want to go stronger and deeper in San Francisco, to establish a powerful proof point. “We need to do what we do, well,” says John Rootenberg. That said, there are plans to open an outpost in San Jose in late 2016, and in Los Angeles in 2017. Additionally, there are seven similar projects around the country that go by another name, but which were inspired and guided by Lava Mae.

Lava Mae’s $1.4 million annual budget is philanthropy-based. Indiegogo campaigns, creative fundraisers (decorated loos, anyone?), and foundation dollars comprise the organization’s funding. In addition to Google’s investments, Lava Mae is in Draper Richards Kaplan’s portfolio. DRK has funded $300,000 over three years, and provides operational plan support and consulting. Bank of the West and Toyota have also contributed substantially. Currently Lava Mae operates under the aegis of the Tides Foundation, but it recently filed for its 501(c)3, which it expects in the coming months.

As Lava Mae looks to paths to sustainability, it is exploring a wide array of ideas—from fashioning a marketing playbook that leverages the Lava Mae brand and creating branch and affiliate models, to using digital screens on the buses to generate corporate dollars. Of note, Sandoval has been known to turn away dollars from companies that don’t reflect the Lava Mae values.

Sandoval and Lava Mae are out to shift the public’s perception of who the homeless are and why they are deserving of our compassion by connecting with the people and getting the people to connect with the issue. They’re doing it one shower at a time.