Nothing turned up during earlier searches of the Brea landfill.
Orange police Sgt. Dan Adams says Monday's search will continue throughout the day.
Arlet Hernandez Contreras and her 2-year-old and 4-month-old sons disappeared last month.
Detectives discovered the stabbed body of the 31-year-old mother Friday at the Los Angeles County coroner's office, where it had been unidentified since it was found April 25 under a tarp in an industrial area.
The woman's 31-year-old boyfriend, Shazer Fernando Limas, was arrested after a Thursday evening freeway chase, and he was booked for investigation of killing Contreras and their sons.
