If you want to ask a professional plumber to install a drip pan for a water heater, this could cost you between $150 and $300. The labor will be where you wind up spending the most money, even though the drip pan won’t add that much to the total cost.
If you are inexperienced, completing a project of this nature on your own may take an entire day, whereas working with a professional may reduce the amount of time needed to complete the task to only a few hours.