This depends mainly on the manufacturer, as some kitchen faucets may require different types of batteries. The majority of modern touch kitchen faucets will use AA batteries as a source for power. For instance, most Delta kitchen faucets will require 4 to 6 AA batteries to operate, depending on the model. Ideally, this number of batteries will last for 1 or 2 years of standard use, which is about 20 times a day. They’ll also start blinking red when the battery is about to die. However, there might be other touch or touchless kitchen faucets out there that use AAA or 9-volt batteries. Moreover, a lot of people may replace the battery system with an AC/DC adapter, which allows you to plug the faucet directly into the wall and save the cost of batteries. For that reason, always make sure to check the manufacturer’s specifications to find out about the source of power.