Installing two 3-stage under-sink water filters in parallel for better flow

[Tripp Knightly]

I've seen discussions / blogs about doing parallel filter installs for whole-house filtration but nothing on doing it for a single-point solution (though I think GE makes a "dual-flow" single stage filter that does just this).

I have a water dispenser faucet with a 1/4" connect. Based on aesthetics, getting a 3/8"-connect dispenser is not an option. Right now I have a fairly-typical 3-stage filter (APEC WFS-1000) installed right underneath the flooring in crawlspace. It uses 1/4" tubing. I'm getting .5gpm, which is not horrendous and about what I expected. But I'd like to improve it. I'm considering getting a second 3-stage unit and connecting it in parallel. I should mention that if I did this, I would use a 3/8" stop connect and split it to a 1/4" to feed each filter unit, then join back to 3/8" and then step down for the final connect @ the faucet.

I suppose one test I should run is taking out the filter and seeing what the unfiltered flow rate to that 1/4"-connect faucet would be. House pressure is good, perhaps too good (don't quote me but I think I got 75lbs last tested).

What do you think? Likely to improve flow rate? I'm thinking doubling or close to doubling would make it worth it. I'm not sure a whole-house filter is in the cards. Another option might be instead of the kludgey paralleling (leak risks too!) maybe I swap to a 3-stage that uses 3/8" throughput, still with the final step-down to 1/4".

 

[Reach4]

Another option would be to add a pre-charged pressure tank that would store a little water. The tank would fill and you could draw some amount more quickly at a given time. After the stored water is exhausted, flow would continue to your coffee pot, or whatever you are filling, at the current flow rate.

Figure about 1/2 gallon stored in a 2 gallon tank.

I suppose one test I should run is taking out the filter and seeing what the unfiltered flow rate to that 1/4"-connect faucet would be. House pressure is good, perhaps too good (don't quote me but I think I got 75lbs last tested).

Good test.

 

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[Tripp Knightly]

Well I took out the filter by connecting the feed to the output via a john guest union coupler. Flow rate was maybe 3% better, so seems like parallel filters is a non-starter.