" How to install an under counter water filtration system. Before purchasing an under counter water filtration kit, look under the sink and study your present faucet setup. There are a wide variety of filtration units to choose from, but make sure that the new water filtration faucet will fit in the holes available in your sink, and that the unit will fit under the sink. The filtration faucet typically uses the hole in your sink reserved for the hand spray. To start, turn off the cold water shut off valve under the sink. Open the faucet to confirm that the water supply is completely shut off. This also allows the faucet to drain and release pressure. Read the specific instructions that came with your water filtration kit. Note any special instructions and apply. From under the sink, remove the cover plate for the accessory hole. Some clip in and some unscrew. Set the new filtration faucet in place. Make sure that the faucet sits firmly and squarely on the surface of the sink and that the gasket makes a solid seal. Hand tighten the retaining nut to temporarily hold the faucet in place. Usually, the faucet has a retaining plate or washer to clamp the faucet to the sink. Make sure that the plate is centered over the hole. Adjust the new faucet on the sink from above. When the faucet is properly aligned, tighten the nuts from below until snug, and then turn the knot 1 turn more. Do not over tighten. If it is a 2-piece faucet, screw on the spout. Once the faucet is positioned, choose a good location to mount the filter. Make sure that the spot you choose is both close enough for the feed lines to reach your cold water supply and filter faucet, and high enough to allow room to unscrew and replace the water filter when it comes time. Following the instructions that came with your filter, locate and mark the positions of your mounting bracket screws. Using a drill bit that is slightly smaller than the width of the screws supplied with the mounting bracket, drill pilot holes in the cabinet. Before you drill, be aware of what's behind the cabinet wall. There are 2 lines attached to your filtration unit. The inbound line feeds the filter with water from your cold water line. The outbound line supplies filtered water to the filtration faucet. We will attach that line 1st. The way that the filter lines attach varies with the filter. Some push him like this; others grew on. Be sure to follow the instructions that came with your filter exactly. Next, attach the filtration unit to the wall of the cabinet. Detach the cold water supply line from the kitchen faucet and insert the filtration supply valve. Hand tighten the nut, and if necessary, make it snug with a wrench. Do not over tighten. Now attach the supply line that goes to the kitchen faucet to the other side of the filtration supply valve. Hand tighten and make it snug with a wrench, but be careful not to over tighten. Attach the filter supply line. In the case of this filter, you unscrew the nut and the compression fitting from the valve and slide them over the filter line. Then, you push the line onto the nipple of the valve and tighten the nut over the compression fitting forming a tight connection. Hand tighten the nut 1st, and then make it snug with a wrench, but do not over tighten this fitting. The connections on the filter units vary so follow the instructions that came with your filter carefully. Before you test the filter, remove the aerator from the kitchen faucet to allow the sediment dislodged by opening the shut-off valve to flush out of the faucet. Open the cold water shut-off valve slowly and look above and below the sink for leaks. Make sure your standard kitchen faucet is working properly. Let the water flush out for 30 seconds. Open the valve on the supply line to the filter. After the water runs clear from the kitchen faucet, open the filtered water faucet. Filtered water should now flow freely from the filtration faucet. "