This just started happening today out of nowhere. When I open the kitchen faucet halfway the water pressure is ok. When I open the faucet fully the water pressure drops dramatically. Any ideas as to what the problem would be and would I be able to fix it myself or do I need to call a plumber? I’ve attached a video of me opening the faucet halfway and then fully, and also another video of the under side of the sink while opening the faucet halfway then fully. Thanks so much in advance for any help.



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    The aerator at the open end of the faucet - take it off and try again. Commented Oct 15, 2020 at 4:55
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    The previous comment suggests a simple test to see if the problem is in the aerator. If the problem does not occur with the aerator removed, then the aerator is clogged. Commented Oct 15, 2020 at 11:39
  • Is this when set purely to hot or cold water, and does this happen for any other faucet or feed (e.g. shower) in the house? If this is the only place,then you've narrowed it down to the faucet or the length of pipe to the faucet from the last junction. Commented Oct 15, 2020 at 14:30

2 Answers 2


You have a problem with the faucet valve. Those single-handle faucets have a valve that incrementally increases flow whilst also mixing hot and cold, depending on handle position.

There are various types of mechanisms to accomplish this, but a common one is the use of a hollow or solid ball with holes/ports that line up with the incoming water ports to varying degree, and lead to the spout (I mention this because your looks like that type, common manufacturer is Delta). Nevertheless, you need to turn off the water supply, remove the handle, and do some investigating. it could be as simple as a blockage that needs to be cleared, could be a new valve assembly, or could be a new faucet. We will need to see the guts...

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    Maybe the fault is in the aerator which would be a simple fix. Rule the aerator out before proceeding to test the valve. Commented Oct 15, 2020 at 11:41
  • An issue with the aerator would affect flow regardless of valve position. If you watch the linked video, flow increases and decreases in inappropropriate ways during valve manipulation. Commented Oct 15, 2020 at 17:59
  • You are probably right, but these modern aerators have more parts and it is conceivable that high flow could have this effect in an aerator. It is so simple to test by seeing if the problem persists with the aerator removed that I think it is advisable eliminating a fault in the aerator before messing with the cartridge. Commented Oct 15, 2020 at 18:53

I just fixed this problem on my sink. The problem is actually a clogged filter in the quick connector under the sink. The quick connector is the black plastic part with the blue tabs (clearly visible in the 2nd video).

To remove the quick connector, simply squeeze the blue tabs and pull down. Then unscrew the other side of the quick connector to remove it entirely from the hose.

Using a small screwdriver, straw, etc, push the 2 white filters out of the quick connector. They can only be pushed out from one side, and take note of their orientation in the quick connector so you can put them back in correctly.

Once the filters are removed, you'll probably notice some debris in one or both of them. Sometimes it can be cleared by simply washing out the filters.

If needed, you can disassemble the filters to clean them. You don't need to remove the rubber O-ring. Using a small 2mm flathead screwdriver (or something similar), firmly press into the tiny groove on the side opposite of the O-ring, until you can wedge it in and pry the pieces apart. Once separated, the filter is easy to clean.

Reassemble everything in reverse order and test the water. It should be working again!

FYI this is a Glacier Bay sink, produced by Home Depot. If any of the parts have worn out (sometimes the O-rings do) or can't be repaired, take the quick connector to Home Depot and they might replace it under their limited lifetime warranty.

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