No cold water through the kitchen sink

January 18, 2018 8:18 PM

The cold water pressure in the kitchen was low. I checked the shutoff valve to make sure it was open, and now there's no cold water pressure at all. What happened, and what can I do about it?

Our kitchen sink is your standard faucet with knobs for hot and cold water.

I noticed the pressure of the cold water drop a few months ago, but tension with the landlord convinced me it wasn't worth fighting over. This evening I thought I'd check to make sure the shutoff valve hadn't been nudged by something under the sink. I moved it back and forth a little, and the water pressure dropped to an intermittent, tiny trickle.

Yes, I checked to make sure I didn't close it by accident. The hose is not kinked.

The hot water pressure is fine. The faucet in the bathroom is fine. It's just the cold water in this one faucet that doesn't work. Is there maybe something blocking the line? What can I do about it? Here's hoping we won't need to call a plumber.

posted by shapes that haunt the dusk to Home & Garden (15 answers total)

Are you in a frigid part of the country such that a pipe may have frozen?
posted by Candleman at 8:29 PM on January 18, 2018

Obvious first guess for someone from New England: is it really cold where you are and is it possible the cold water pipe runs through someplace even colder and/or unheated?

Also: cold water is a basic thing you get with an apartment. If your cold water isn't working, that shouldn't be a fight with the landlord just "I need to get cold water in the kitchen. Can you please handle this?"
posted by jessamyn at 8:29 PM on January 18, 2018 [1 favorite]

Response by poster: Sorry, forgot to mention, but I am not in a cold part of the country. In rainy, but temperate California. (Realistically it won't be a fight if I have to get it fixed, but there's currently some tension between tenants and landlord, so I'd prefer to limit contact if possible.)
posted by shapes that haunt the dusk at 8:33 PM on January 18, 2018

Best answer: What I would try:

First, get a bucket. Turn off the shutoff valve, disconnect the hose from the faucet and drop it into the bucket, and briefly turn the shutoff valve on. If you get normal pressure flow, the problem is the faucet. Easy fix.

If still slow, close the shutoff valve, remove the hose from the valve connector, and hold the bucket up to the valve opening. Slowly open the valve. If you get normal pressure, the problem is the hose. Easy fix.

If you still get slow / no flow, it might be plumber time. Could be the valve itself, but DIY replacement depends on how handy you are and how the valve is connected to the supply line. (Personally, I wouldn't mess with it. I finished my whole basement more or less by myself, including rough-in plumbing, but the final plumb job (connecting the fixtures to the supply taps) I hired out. I'm not risking a basement flood because I missed a gasket or didn't seat a compression fitting properly since I didn't know what I was doing.

On preview, I missed that this is a rental. Yes, this is what you call the landlord for. This is their issue to resolve.
posted by SquidLips at 8:39 PM on January 18, 2018 [4 favorites]

Best answer: If you take the knob off the cold water handle, are there any stops or adjustments that might be having it only have a limited turn? Does the shutoff valve make multiple rotations, or only through 90 degrees? You might check to see if it is fully open at some partial angle.
posted by nickggully at 8:40 PM on January 18, 2018

Best answer: The supply line is probably clogged by debris (junk that builds up on the interior of the water line, and get knocked loose). The debris is probably backing up right at the valve of the shutoff valve.
posted by misterbrandt at 8:56 PM on January 18, 2018 [2 favorites]

Best answer: My guess is that the rubber washer which is held by a screw onto the end of the shaft of the shutoff valve has cracked, and a piece of pie shaped section of that washer is now trapped at a constriction somewhere between the shutoff valve and the faucet.

It was probably already partially loose but still attached to the shaft and reducing the flow, but when you jiggled things, it broke free altogether.

Turning off the cold water upstream of the shutoff valve will allow you to replace the washer easily enough, but getting the fragment of the old washer out of the water path might be tricky.

If the fragment doesn't just fall out in the process of replacing the washer, I recommend replacing the washer and shutting off the valve, turning the water back on, then unhooking the tube which leads to the faucet from the shutoff valve and putting a large bowl under the open end of the tube, then putting your finger over the faucet and turning on the hot water. At that point, the hot water should blow the fragment out into the bowl.
posted by jamjam at 9:11 PM on January 18, 2018 [1 favorite]

Best answer: On second thought, if you turn the valve all the way off and it stops the trickle completely, you might be able to get away with simply leaving the valve shut, loosening the tube from valve to faucet and placing the open end in a big bowl the way I suggested, and using the hot water to blow any obstruction into the bowl.

Then replace the tube and see where you are.
posted by jamjam at 10:17 PM on January 18, 2018

Response by poster: Well, I shut off that faucet and disconnected the hose at the shutoff valve. Getting at the faucet is more of a commitment, because it's behind the sink. It seems like the blockage is in the hose, but I haven't been able to clear it. I've tried the hot water method you suggested, jamjam, but the pressure just sprays out at the faucet. I'm not sure what to make of that.

Anyway, I was able to restore the cold water pressure to pre-earlier-this-evening levels, which aren't great, but at least it's flowing again. No one was more surprised than me.

Emboldened by this minor success, I think I'll fully commit to this and see if I can check the other end of the hose tonight, although I might not have the right kind of wrench for it. I'll probably still have to call a plumber.

At least I can fill the kettle in the morning. Although I meant to ask - if there's a blockage of some sort, should I be concerned about the safety of the drinking water through that tap? I'm assuming whatever is blocking it has been there for a while, but you never know if it's going to turn out to be something gunky or what.

Regardless of how this turns out, I am extremely grateful for everyone's advice, and I will report back with updates, if anyone is interested in my poor-excuse-for-a-handyman saga.
posted by shapes that haunt the dusk at 10:33 PM on January 18, 2018

Best answer: What kind of shutoff valve is it? Sometimes old gate valves can break inside when you close them, rendering the valve permanently closed. In galvanized steel piping systems, they tend to build up rusty crud inside the little groove inside the valve, which can both block the flow of water and make it impossible to close the valve 100% (meaning it will drip even if turned off). If this is your situation, you need a plumber.

Or maybe you have a compression valve, or a modern quarter turn angle stop? That would be a different situation, though you could still have crud clogging the valve itself.

But also: Call your landlord, this is their job!
posted by cnidaria at 10:36 PM on January 18, 2018 [1 favorite]

Best answer: Did you remember to turn the cold water faucet at the sink to an on position before you tried my trick?

At least some of the hot water should have come out of the hose if the cold water was turned on at the sink if a trickle is getting through when the cold water shutoff valve is open.
posted by jamjam at 10:57 PM on January 18, 2018 [1 favorite]

Response by poster: Update: I fixed it! The hot water trick worked! Thank you, jamjam!

And heh, yes, I think I know why your trick didn't work the first time...

The question that remains is, should I still call a plumber as long as it continues to work and isn't leaking? I still don't know exactly what happened, but at this point I'm not sure what a plumber could do besides make sure everything is in order. There wasn't any washer to replace, as far as I could tell. Is it reasonable to assume that it was just some crud from the pipes that broke off and got lodged in the cold water hose?

Completely agree that this is the landlord's problem. I was just motivated by wanting to be able to fill the kettle in the morning, and maybe also to have an excuse to be handy for a change. I fully was not expecting that I'd actually fix it. Of course, I couldn't have done it on my own...

(Incidentally, I'm no valve expert, but as far as I can tell, it's just your standard compression valve, like what I usually see as a shutoff valve.)
posted by shapes that haunt the dusk at 11:03 PM on January 18, 2018 [2 favorites]

I've been a handy tenant over the years in order to reduce the number of contacts with building management. including unclogging a supply line in this exact scenario. Once I fixed it, I had no desire to ask for a plumber.

Those supply hoses are ~$10. If you'd like the peace of mind, you could get a brand new one and swap it in.
posted by reeddavid at 11:24 PM on January 18, 2018 [1 favorite]

Is it reasonable to assume that it was just some crud from the pipes that broke off and got lodged in the cold water hose?

Yes, especially if you noticed any little bits of unidentifiable urk in your collection bucket after the swirling all settled.
posted by flabdablet at 1:44 AM on January 20, 2018

This is not uncommon with modern sink valves with ceramic disks. The tolerances and openings are pretty small. When you first wiggled the shutoff valve, you probably loosened a flake of mineral scale and it broke off and the embolism got stuck in the cold water valve in the faucet.

Jamjams trick worked because by disconnecting the cold water supply and turning on the hot water half way so that both hot and cold valves in the faucet were open, you were forcing hot water backwards through the cold valve in the faucet and into the bucket. This dislodged the flake stuck in there. It sometimes is necessary to hold your thumb on the spout to force more pressure back through the cold valve. Note that you need to have both hot and cold valves open on the faucet for this to work.

You can also clean this out by disassembling the faucet valve, but I like jamjam's trick as a first resort as it is a lot easier.
posted by JackFlash at 11:37 AM on January 20, 2018