Make sure you are hiring skilled plumbers, not just a general handyman. How do you find this out? Go to the California State License Board to find out if the plumbing contractor or plumbing company has an active contractor’s license for California plumbing. The Contractors State License Board will also show information about the company’s workers compensation insurance and bond insurance. Plumbing companies that use employees to do the work must carry workers compensation in case an employee is injured. You want the plumbing company to take the risk of having their employees at your home, not you!