Homecare, court and other county workers will jump on the "Fair Share Express" and shuttle between the five cities starting at 9 a.m. in Daly City, the district of Supervisor Adrienne Tissier.
Subsequent stops in Millbrae, San Mateo, Menlo Park, and East Palo Alto are meant to draw the attention of supervisors Mark Church, Carole Groom, Rich Gordon and Rose Gibson, respectively.
The county is looking at a budget deficit of more than $100 million for the next fiscal year, a county spokesman said last month.
In July, county supervisors voted against pursuing a sales tax measure, arguing that the county could make additional cuts.
The workers argue that the county budget is bloated by a high ratio of expensive managers to frontline employees, according to a statement issued by the workers union, Service Employees International Union Local 521.
That union represents more than 60,000 workers and specializes in homecare in San Mateo and Santa Clara counties.
Participants plan to wear rain ponchos and hold umbrellas to signify that current times are "rainy day" times, according to the statement.