Under-sink water filters provide filtered drinking water routed through a separate tap at the top of the sink. In some instances an under-sink filter may be connected directly to the cold water line on the main faucet instead. In either instance, cold water passes through a filter or series of filters before reaching the separate tap. Depending on the make of the filters, replace the filters every few months for proper filtration.
Turn off the cold water valve under the sink. If in doubt as to which valve is hot and which is cold, turn both to the off position. If you can not locate a valve in near proximity the sink, turn off the main water shut off valve in the basement or outside the home.
Grasp one tube at a time and gently twist until the tube cover slides off, revealing the filter underneath.
Turn the water supply valves you closed in Step 1 back on. Press the filtered water tap lever and hold it for a few seconds to begin water flow through the filters. Turn it off when water comes out of the faucet.