Rent plus childcare is simply too much for many in Marin. According to data compiled by the First 5 Marin Children and Families Commission, a family of four with an infant and a preschooler needs an annual income of $102,223 to afford the basics of family life. Nearly 35 percent of such families in Marin—there are around 10,000—do not meet that standard. The commission, which guides the county Board of Supervisors on the investment of Proposition 10 funds, presented the findings on Tuesday in collaboration with the Marin Economic Forum, which contributed data. The report, “Making Ends Meet in Marin,” came before the board this week at the request of Supervisors Damon Connolly and Katie Rice, who is ceding her position as a board representative for the commission to Supervisor Dennis Rodoni this month. “We live in an age where wages are not high enough to support a family with a single income, which means that there is not one parent home with the kids,” Supervisor Rice said. The commission used estimates that families spend $16,000 for licensed child care or preschool and another $20,000 for an infant each year. Add to that the fair market rent of $3,000 a month for a two-bedroom unit. If a family wants to limit their spending on rent to the gold standard of 30 percent of income, that puts earnings at $102,000. Oh, and want to own that home? The median home price for a single-family home in Marin is $1.2 million; to purchase such a home, a family needs an annual income of $260,000. The commission used data in part from the Marin Economic Forum, where a student consultant named Jesús Guzmán from Berkeley’s Goldman School of Public Policy is measuring the economic costs of the housing shortage. Mr. Guzmán is looking at three factors: the loss in consumer spending, the cost to employers, and economic inequity. To explain the latter, he said giving everyone a pair of shoes represents “equality,” whereas “equity” is giving everyone a pair of shoes that fits. Mr. Guzmán provided some interesting statistics. Around 61,000 people commute into the county daily; if 20 percent of them moved to Marin, the county’s economy would get a boost of $280 million a year. Contributing to a loss of consumer spending are the 52 percent of Marin renters who pay more than 30 percent of their income on housing (and 41 percent of homeowners). As far as costs to employers, 91 percent of California companies report some difficulty recruiting employees, and 50 percent say they have lost a candidate or had to pay more specifically because of high housing costs. Workers who commute less than 30 minutes gain an additional seven days of productivity, Mr. Guzmán said. The average commute time in Marin is 31 minutes.