I installed a new single-handle kitchen faucet with a sprayer. Is it possible to replace the sprayer with a water filter (I have only one hole on the side in the sink)?

Specifically, would it work to connect an under-sink water filter inlet line to the faucet's sprayer outlet? That is, as opposed to connecting the filter inlet to the main cold water inlet (via a T connector).

Reason: I want to avoid touching the connections between the inlet copper pipes and the "tubes" that go to the faucet, if possible.

  • There's a valve that shuts the sprayer water when you don't have the sprayer lever open (this keeps the sprayer from leaking). If you connect after that valve, you may have trouble. Apr 8, 2016 at 0:41
  • @Daniel Griscom Yeah, my question was basically about that valve. Would the knob on the filter fixture act like the lever on the sprayer?
    – alexei
    Apr 8, 2016 at 0:55
  • 2
    My guess is that the filter will have a significantly lower water flow, and you may get oscillation of that valve as the pressure builds up and discharges. Apr 8, 2016 at 2:29
  • @DanielGriscom Ah, makes sense. Reason enough to not hookup to sprayer outlet.
    – alexei
    Apr 8, 2016 at 23:00

1 Answer 1


The diverter valve built into your faucet is downstream from the faucet valve that is designed to hold back "line" pressure. The diverter shunts water toward the spray head when you open the spray head valve, and directs it toward the fixed spout otherwise.

The faucet sprayer head/nozzle is not designed to hold back system pressure. They would have to be more robust to the point of being unwieldy to do that. Also, the main valve is where hot and cold are mixed, giving you temperature adjusted water at the sprayer head. If you hook directly to the spray head it will leak.

  • Ok, I'll just hookup the filter to main inlet via T. That said, I don't fully understand why hooking up to sprayer outlet from faucet would leak. Everything you said about the dirverter valve makes sense, but why can't the filter (that is designed for line pressure, and has a handle valve) be downstream of the faucet valve (besides the drawback of having to turn two handles to get filtered water)?
    – alexei
    Apr 8, 2016 at 22:58
  • Actually, after carefully rereading your proposal, my thoughts are that it might work. The diverter valve is basically spring loaded; when there is no opportunity for flow out to the sprayer head (sprayer valve closed) it is seated, protecting the sprayer head from full line pressure. When the sprayer valve opens, the pressure differential allows the valve to open, shunting some flow out that way. The challenge/variable is whether or not the flow/pressure drop across the filter media and hardware will allow the diverter valve to function properly, as mentioned by @Daniel Griscom. Apr 15, 2016 at 6:36

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