How To Install An Under-Sink Water Filtering System

Why pay a plumber's fee when you can install your own under counter water filter?

Need a water filter? You can install your own under-sink filter. I'll show you how.

What you'll need.

You'll need to buy a filter and a tee joint for the connection (unless one comes with the filter). Besides that, you only need a few simple tools such as a medium size phillips screwdriver, pliers, and a medium size adjustable wrench

Purchase the filter.

Find the right filter system to fit your situation. Be sure there is ample room for the filter to fit underneath your sink.

Also, before buying a filter, read the section (below) about locating the filter faucet. Be certain you have a place for it. (If not, you may want to reconsider and purchase an above the sink unit.)

Be sure the filter has a flexible tube to connect to the cold-water line under the counter. It also needs to have, or you need to purchase, a tee joint to connect between the cold water cut-off and the sink's water supply tube. This tee joint is where you will connect your water filter. If no tee joint comes with the filter, your supplier can direct you to the right size to buy.

Decide where the filter will be placed.

Some filters are designed simply to stand on the floor in the under-sink area. Some are designed to hang on a side or back wall in the under-sink area. Ultimately, you must decide where the unit fits best.

Clear the area where you want the filter to be placed and be sure it fits. If you are going to hang the unit, go ahead and follow the manufacturer's instructions about installing the unit. Usually a template will be provided showing where to place screws the unit will hang on. For hanging models a bracket and screws will be provided.

Locate the filter faucet.

A special filter faucet will be included with the unit. Study the manufacturer's instructions on how the filter faucet will be placed.

Many sinks have an opening for secondary installations such as a water filter or a spray unit. If desired, you may use this opening for your water filter faucet. If there is no such opening in your sink, one must be cut in your counter top behind or very close to the sink.



If a hole must be cut, do the job yourself only if you have the necessary tools and experience to do the job successfully. If you do not have the tools and experience to cut this opening, it is recommended that you enlist the help of a friend who does have the tools and experience, or hire a qualified person to do the job.

Once you have the proper opening for the filter faucet, you are ready to install it. Place it in the hole with the faucet up and over the sink and tighten up underneath according to the manufacturer's instructions. Be sure to make it tight enough to be steady, but do not over-tighten, especially if the sink is ceramic, or made of other more fragile material.

Connect the filter faucet.

This is fairly simple, because the filter will come with all the necessary equipment and parts to connect the faucet. Follow the instructions to make this connection.

Connect the water supply.

Be sure the cold water supply to the sink has been turned off. Usually you can do this by locating a cut-off under the sink. Turn it off, then test to see that the cold water has gone off.

When the water is off, take the cold water supply tube loose from the cut-off. You'll need your medium size adjustable wrench and maybe your pliers to disconnect the hose. Turn counter-clockwise to disconnect the cold water supply hose or tube.

Connect the tee joint to the water supply cut-off, being sure the side connection points in a direction that will let you get to it to connect the filter hose. Next, reconnect the cold water sink hose to the other end of the tee joint. Now you're ready to connect the filter supply hose to the side connection of the tee joint.

Test the connections.

Tighten all joints securely. Test the connections by slowly turning the cold water back on at the cut off. Check all connections to be sure they are tight and not leaking.

If there are leaks, turn the water off again, tighten the joints that are leaking, and turn the water on again. If leaks continue, try this: disconnect completely and reconnect to make a more secure connection.

Watch the connections for a few minutes while the filter fills up, to be sure they are continuing to hold without leaking.

When all the connections hold and water is flowing from your new water filter, you have successfully installed your filter.

© High Speed Ventures 2011