Dave Costello is a go-to guy for deluxe insurance. President of Northstar Insurance Services Inc., and partner/broker for AIG Private Client Group, Costello insures mansions, consolidates insurance for high-income individuals around the world and mixes at exclusive bashes.
His four-story waterfront residence in Tiburon is both a restful haven and a nexus for sports, guests and socializing.
The home is nestled on a promontory that faces east and south and features views of San Francisco Bay and Contra Costa County. The property is hilly, with a downward-sloping terrain.
Three successive terraces of diverse gardens, plantings and structures divide the property into unique respite and activity
At the highest terrace, a majestic grove of 100-year-old oaks shades a pathway to the upper entrance of the house. Pines and conifers run into a perimeter planting of English lavender that stands guard and peeks over to the lower terraces.
On one side of this terrace, carved out from a steep rise that’s approachable from the drive, is a charming five-hole putting green, which Costello calls “a chipping green to relax after a full day.”
Most of the focus is on a mid-level terrace, where a manicured lawn meets an unfinished slate pathway and patio that frames a large, rectangular pool.
A man-made flowing stream cascades from the upper level terrace to mid-level, which boasts a fountain. Seventeenth-century pure-lead statues Costello bought years ago at Bonhams stand at attention by the retaining wall.
Bougainvillea planted against the wall bring a bright flush to its surface. Pots of annuals punctuate the green grass with the colors of summer, in reds, oranges and yellows. Boxwood, some succulents and hydrangeas also are in the mix.
On the lower terrace, pines run down the grassy knoll to the path to the beach. Hydrangeas and annuals are planted at side and foot of the home, in urns and the ground. But there’s enough flatland for Costello to have a full-size, dirt bocce ball court at the ready.
Costello, a third-generation insurance man, also serves on the board of SF Commerce Bank and is a partner in Golden Anchor, which reinvests equity for yachts and airplanes. His Northstar partner, Dave Witter Bates of the Dean Witter family, likes to say Costello is an under-the-radar celebrity.
“Every day, I live a charmed life,” Costello says. “There’s no doubt about it. I’m grateful every day. I love people.”