Months after the state housing department deemed the city of San Mateo’s housing plans “substantially compliant,” the City Council voted this week to unanimously adopt the latest round of revisions before sending it back to regulators for final certification.

The city is planning for 10,000 new units, about 40% more than its 7,000-unit regional housing target, with a significant portion planned along the busy El Camino Real thoroughfare.

Every eight years, local governments are required to submit a housing element, a document that outlines how cities will add a specific number of homes at various price points. The city’s housing plan is already more than a year overdue.

Not having a certified housing element means that a city could be subject to consequences like the builder’s remedy, which allows developers to ignore a city’s zoning rules as long as 20% of the units are set aside as affordable.

In recent years, state regulators have been scrutinizing cities’ housing plans more closely than ever before, as the state struggles with soaring housing costs and a housing shortage.

“I think it is a very strong document. You never know what’s going to happen in the future, but we’ve got a very good plan for the 7,015 units, and we’ve got a 40% buffer,” San Mateo Mayor Lisa Diaz Nash said of the latest revision. “While we can’t tell developers where to build or how to build, we just have to demonstrate it’s feasible.”

Some residents and community organizations raised concerns over the supposed lack of rezoning plans and the city’s property inventory, or sites identified for housing construction, being occupied already. On Tuesday, the pro-housing organization Housing Action Coalition sued San Mateo, alleging the city can’t realistically expect to build on sites it is targeting for new housing.

“The housing element overestimates how much housing will be produced,” said Ali Sapirman, the South Bay and Peninsula organizer of the Housing Action Coalition. “It includes sites that are not available because they’re already being used for something else.”

Sapirman’s organization asked the council to vote against the city’s latest housing plan.

But Diaz Nash explained that the inclusion of properties with existing buildings is because the city is “all built out.”

“It is reality,” Diaz Nash said. “There are very few places for us to go that aren’t already built.”

She explained that the city’s site inventory is constantly evolving.

“It’s not like that’s the end of it,” Diaz Nash said. “We’ll go back on an ongoing basis and monitor it. If something becomes a possible site, or someone raises their hand and says they want to develop here, we’ll add it to the map. If someone turns it into a commercial building, we’ll take it off the map.”

In response to criticism that the plan maintains a “status quo” on zoning, Diaz Nash said she disagrees with that analysis.

While the housing element says rezoning isn’t required to meet the goals, Diaz Nash said the city does plan to rezone certain areas “along El Camino, Bridgepointe, Hillsdale, and along the Caltrain lines.”

Later in the year, the City Council is eyeing putting an amendment to Measure Y on the November ballot, which would allow taller and denser projects to be built along El Camino, in hopes that planned housing projects would be integrated with transport, commercial and office developments.

The mayor stands by her long-held position that tall buildings should not be built in single-family neighborhoods.

“I mean, we don’t want to put up 12-story buildings (in single-family zones),” Diaz Nash said. “That just means everybody will get in their car and there’ll be a lot more cars on the road.”

The city plans to submit the latest housing element by the end of June and hopes to receive certification sometime in July.