O.C. McDonald Company has been one of the Bay Area’s leading plumbing, process piping and HVAC contractors and service providers for over a century, making it the oldest such company in the valley. Founded in 1906 in San Jose, California, O.C. McDonald installed the first air conditioning system in the city. It was founded by Oren Charles McDonald in 1906 and is currently owned and run by Jim McDonald, the founder’s great grandson. We are known for having excellent quality workmanship and have accomplished some of the most complicated installations in the valley.We’ve built our reputation on combining old fashioned values with innovative technology; together, these provide our clients with consistent quality, excellent customer service and a contractor that is on time and on budget.