The answer to 'types of water line' is that there are several common types of water lines used in residential plumbing systems. The most common types are copper, PEX (cross-linked polyethylene), and CPVC (chlorinated polyvinyl chloride).
Copper pipes are a traditional and durable option, but can be more expensive to install. PEX is a flexible, plastic-based pipe that is easier to install and less prone to freezing. CPVC is another plastic-based option that is corrosion-resistant and relatively inexpensive. The best type of water line for a home will depend on factors like the home's age, local building codes, and the homeowner's budget and preferences.