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I recently replaced my water heater, and since then, the water pressure for my kitchen faucet is really, really, low. None of my other faucets seem to be affected (bathroom, shower, etc.). I can't really tell if my dishwasher is affected, but my refrigerator does not appear to be. The kitchen faucet, dishwasher, and refrigerator all run off the same set of pipes that come into the cabinet below my kitchen sink. The water heater is located a floor down almost directly below the kitchen.

My current theory is some sediment dislodged from the replacement of the water heater has blocked the faucet. Is this possible? Could this be caused by anything else?

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Is the water pressure in the kitchen low for both cold and hot water? Your fridge wouldn't be affected regardless as it only gets a cold feed and would be fed prior to the hot water heater feed. – The Evil Greebo Nov 1 '11 at 16:22
Have you checked the aerator on the faucet? – Tester101 Nov 1 '11 at 16:30
The water pressure is low for both hot and cold. I looked at the aerator, but I have not removed it. I did not see any blockage just by looking up at it. – Dave Nov 1 '11 at 16:54
Was any of the plumbing to your kitchen modified as part of the heater install? – Tester101 Nov 1 '11 at 17:12
I removed the aerator, and there was some debris (very small, sand like pieces- not very much). After getting rid of the debris, the pressure is still low. – Dave Nov 1 '11 at 22:43
up vote 3 down vote accepted

What type of faucet do you have? If you have a pull-out faucet then you can detach the pull-out head from the hose (that reaches down under the sink) and see if the water pressure is good at that point. There are small parts in the pull-out faucet that also could have caught some debris (although cleaning them out may be a challenge). But at least you could have narrowed down where the problem is; i.e. is it in the pull-out faucet head.

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My faucet is almost identical to this one: us.kohler.com/onlinecatalog/… – Dave Nov 3 '11 at 14:31
Looks like you have a pull-out faucet. Just unscrew the faucet head from the line to try and narrow down where the blockage is. – Jeff Widmer Nov 3 '11 at 15:11

9 times out of 10, like Tester mentions, this is going to be the aerator. Unscrew it, run some water without it, and clean it before screwing it back on. There's all kinds of stuff that gets knocks around in the pipes when water is shutoff and things are added or replaced in the plumbing system, and the best place for them to end up is the kitchen sink aerator since it's so easy to fix.

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Thanks for the answer BMitch; unfortunately, it did not work. Please see my comment above. – Dave Nov 1 '11 at 22:44
That's not good news, since all the other places for the blockage are more difficult to reach. The next places to check will be the cartridge if this is a single handle design, and the diverter valve (not sure if there's a proper name for that) if you have a separate sprayer. – BMitch Nov 1 '11 at 23:05

Blockage of some sort is probably a pretty good guess. Trying to think of other solutions though since that doesn't seem to be it...

There's a chance that the plumber "fixed" the pressure reducing value (PRV) on your mainline, although that seems less likely since your other fixtures aren't affected. However, depending on the size of the line running to each location, an adjustment to the PRV could be more noticeable in some locations that others. (I tend to turn adjust my PRV quite a bit towards high-pressure end, but this could be a bad idea depending on where you live. You'll also tend to use a bit more water.). If pressure hasn't changed anywhere else in the house though, some sort of blockage is most likely. Perhaps the new water heater has a smaller outflow line? Again, not likely, but something to look at.

[Edit] Just noticed your comment about your kitchen having been remodeled recently. The plumber/contractor most likely used Pex with 90-degree clamped elbow fittings - there could be a chunk of something caught in one of those bends. They'd have to be pretty careless for that to happen though... Is there use a pex manifold block in your system? They may not have turned the valve(s) to your sink to the full 'on' position.

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Listen, I'll make your life easier.....Turn your both shut offs off from under your sink and Just unscrew your water line or lines that are under your faucet.....Put a pail under the line and turn your shut off on slowly and see if your water pressue is any better....If it is just replace your faucet and your good to go!

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The average person will not be able to compare the flow rate of a faucet with an aerator, to the flow rate coming directly from the pipe. – Tester101 Jan 23 '14 at 11:45

It was the aerator for me. I had removed the dishwasher hook up from below the kitchen sink and put in a stopper in place. To do this I had to turn off the water at the multi turn valve, which pushed some debris into the faucet aerator. Once I cleaned the aerator, the flow came back to normal.

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depending on where you live, it could be hard water buildup. I recently replumbed my shower and when i tested my kitchen sink, it worked fine... then the flow slowed 80%. When I checked the aerater had bits of blue to light blue bits of sand like debris... and knowing from changing my water heater at another time, it was hard water deposits. this just happened an hour ago, so no solution yet... but dreading it. hoping i can hook my shop vac up to the water line and suck something out... probably not a great idea but..oh well. location: Central Florida.

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From the comments, the OP checked and cleaned their aerator but the problem continued. – BMitch Feb 26 at 17:04

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