Dirty hallways, bad plumbing, non-working light switches — all are hallmarks of problem properties, and Los Angeles has thousands of them.

Under an ordinance passed by the City Council on Tuesday, these buildings will be inspected every two years by city staff, rather than every four years.

"Over the course of the next several years, the tenants who reside in buildings deemed blighted or low-quality will see a dramatic improvement in living conditions," said Rushmore Cervantes, head of the city's Housing and Community Development Department.

The housing department is responsible for periodically inspecting every apartment building with two or more units. In a city where more than half the residents are renters, that's a lot of apartments. The housing department has recorded 100,000 buildings, with 750,000 units among them.

Cervantes said the majority of landlords are doing good jobs maintaining their buildings, but 4 percent are neglectful.

"Sometimes it can be a lack of financial means or it could be lack of knowhow," Cervantes said.

The new law calls upon city staff to provide technical assistance to landlords, such as helping them identify financing options for repairs.

The ordinance codifies the department's years-long practice of inspecting apartment buildings every four years, while adding a provision that problem properties be subjected to inspections more frequently.

Cervantes said his department will provide the extra inspections and counseling for landlords without adding staff.