Installing an Under-Sink Water Filter
Follow these basic steps to add a dedicated drinking-water faucet to your kitchen sink.
An under-sink water filter can be attached to the cold-water supply of the main faucet, but in that case, it would filter all the cold water you use for cleaning as well as drinking, which would require you to change the filter more frequently. Here, we show how to install a filter with its own dedicated drinking-water faucet.
Under-Sink Water Filters
The steps shown below show installing a simple single-stage filtration and absorption system, which will filter out most particles. It has a single small filter that takes up little space and needs to be replaced only twice a year or so. Two- and three-stage filters have, unsurprisingly, two or three canisters. Some filter systems add a tank as well. Here are some common filter options:
The faucet will require a hole in the sink’s deck. The sink shown here came with four holes, so one was available. Some porcelain or fireclay sinks (like the one shown here) have knockouts, which you tap with a hammer and cold chisel to produce a hole. If none of these options are available, you may need to drill a new hole in the sink or countertop.
The water path is easy to follow: It runs from the cold-water pipe to the filter, and then to the faucet.
Excerpted from Plumbing (The Taunton Press, 2016) by Steve Cory.