Mariska Hargitay on Life at Home with Husband Peter Hermann and Their 3 Kids: 'It's Happy Chaos'

When Mariska Hargitay isn't fighting sex crimes on screen as Olivia Benson in Law & Order: SVU or off-screen with her Joyful Heart Foundation, she enjoys time at home with her husband Peter Hermann and their three kids.

"Being at home, this is my happy place," the actress and activist, 56, tells PEOPLE in the cover story of this week's Women Changing the World issue. "The idea of being home changes everything, and I can see it with my kids too, that idea of, 'Oh, okay, Mama's home, everything is fine.' And in this house, it's happy chaos when everyone is here."

The Golden Globe winner calls being a mom to sons August, 13, and Andrew, 8, and daughter Amaya, also 8, "the most important thing I'll ever do."

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But, she admits, that balancing all of her responsibilities can be difficult at times.

"There's not enough hours in the day," Hargitay says. "I'm on a TV show, and I have a foundation and three children and a husband, and they all need, as anything that you value does, a lot of focus and energy. Time is my most precious commodity now. I've had to think smarter to get more done."

No matter what her schedule brings, "I've always wanted this to be the joyful house," she says. "So that gives me peace."