Harry Clark started a plumbing service company called Grand Ave. Plumbing in 1946. The company moved to Piedmont Ave. and changed the name to "Harry Clark Plumbing". Harry Clark along with his wife Madeline, ran a successful neighborhood plumbing company. Some years later Mr. Clark passed away. Madeline Clark, came from a family of plumbers and had worked with her father when growing up. Madeline was not ready to retire, or sell. She applied and succeeded in becoming a California licensed plumbing contractor. She was one of the first in this state.

In 1976 Mrs. Clark was ready to retire. She found Donald and Beverly Marshall, who worked in the industry since 1952. They bought the company. They continued the tradition of the local plumbing company specializing in service. They hired their youngest son Brad Marshall, a union trained journeymen in 1985. By 1989 Donald and Beverly were ready to retire. They sold the company to their two son's, Brad and Don Marshall.

Today, Harry Clark Plumbing and Heating Inc. retains its roots as a specialized service company. They have expanded the service base to include: sewer repair and replacement, heating and air conditioning service and installation. Today's company enjoys the status of a premier service contractor serving the Bay Area's needs.