Faucets are ubiquitous plumbing products having the basic purpose of delivering hot, cold, or mixed water from a water supply (such as tap or well water) to a user. Some faucets, especially kitchen faucets, feature pull-down or pull-out spray mechanisms, which provide users with more flexibility in directing water output. Because tap and well water often include impurities, such as chlorine and other contaminants that could affect the taste, appearance, and safety quality of the water, people often choose to install water filtration devices to purify their water. However, conventional filter devices are either mounted at the faucet spout, which limits access to the sink, or under the sink deck and coupled to a side faucet separate from the main faucet, which occupies valuable deck real estate. These filter devices are also incompatible with pull-out faucet types.