Gurgling Sink Drain?

[Bird]

We have an exceptionally loud gurgling sound coming from our kitchen sink drain. It happened off and on for 3 or 4 days a couple of weeks ago, then quit, but it's back this morning. I can find all kinds of possible causes and fixes on the Internet, but everything I've found is for gurgling while draining. Problems range from stopped up roof vent to garbage in the drain pipe from the disposal to the other sink, to P-trap obstruction, etc. Ours drains just fine, as does every other drain in the house. It's while there is no water running that it's so noisy.

Any ideas as to cause or cure?

 

[MikeInEburg]

I'm in the "blocked vent pipe" camp. Since drain can't vent thru roof pipe, it's venting thru your drain, maybe drawing your trap empty at the same time.
Mike

 

[kenstrac]

I have had one drain do that,when the wind would blow in the right direction and speed the upstairs drain would gurgle.
Another possibility could be a negative or positive pressure in the house,exhaust fan ,dryer ,etc.

 

[Bird]

Mike, I'd agree that's a possibility, but if it were the roof vent, why would it have quit for a couple of weeks, and then started again.

Ken, now there's a possibility I hadn't thought of. The official temperature this morning was 26 at the airport. My thermometers showed 20-22 on the patio. Calm, no wind, so I don't think that could be the problem. However, I think our house is pretty well insulated and pretty tight. I noticed that gurgling about 6 a.m., but didn't think about whether the HVAC (heat pump) was running or not. Anyway, a few minutes ago, the heat turned off, and now no more gurgling. So I'm hopeful. Of course, the heat has been on in the past, too, when the drain was not gurgling, so I guess time will tell.

Thanks to both of you.

 

[Bird]

A few minutes ago, I noticed that sink drain gurgling to beat 60 and the HVAC system was blowing warm air. I turned off the heat, opened the back door and the kitchen window and in a couple of minutes the gurgling stopped. Looking more all the time like you diagnosed it, Ken. I would have never thought of that. Once again TBNers come through for me. Thanks again, Ken.

 

[CurlyDave]

Bird:

Are you on septic or sewer?

A loud gurgling sound like that implies at least an inch or two of water column pressure difference between the drain pipe and the house.

If the house itself had that much pressure difference between inside and outside you would notice doors being either hard to open or slamming shut. And, if it really is a house to outdoors pressure differential, you should see immediate relief upon opening the door or window.

If you have septic look for a blocked vent on the tank. If it is sewer, you still have a drain line to house pressure difference, but your options on correcting the problem are more limited.

 

[Bird]

Dave, we're on the city sewer line. That's one thing I thought about initially because in the 5 years we've been here, we've had no sewer problems ourselves, but have just very frequently seen the city truck out here, within a couple of hundred yards of our home, flushing the sewer line. And this summer they replaced and re-routed some of the sewer lines within a hundred yards of our house. One thing I considered, but still haven't tried is to go out and removed the cap on our own sewer clean out line.

But, nope, no problem with the doors in the house.

 

[Kays Supply]

It could be a duct that has came loose under the house or in the attic. That would make a pressure differential between the feed and return lines in your house. If it is a negative pressure and you are on city sewer you should get a sewer gas smell from the drain that is gurgling. If it is a positive pressure ,no sewer gas, it could be a blocked filter in the cold air return.

 

[Bird]

It could be a duct that has came loose under the house or in the attic. That would make a pressure differential between the feed and return lines in your house. If it is a negative pressure and you are on city sewer you should get a sewer gas smell from the drain that is gurgling. If it is a positive pressure ,no sewer gas, it could be a blocked filter in the cold air return.

Nothing like a good puzzle, huh? Furnace blowing warm air, drain gurgling, no sewer smell at the sink. So I went out and removed both plugs or caps from the clean out line. That did not change the gurgle, but you could sure smell the sewer out there; as you'd expect. So I felt for air coming from each register in the ceiling; one in each of 3 bedrooms, one in each of 2 bathrooms, two in the living room, and one in the kitchen/dining area. Naturally, some put out more air than others, but air coming out of each of them. Then I went up in the attic. We have the round aluminum looking flexible ducts. Couldn't find any of them loose. There are 4 return air registers, very low on walls in the entry way and each bedroom. I checked them with a candle and, yep, holding the candle in from of them, you could see each one trying to pull the flame. Furnace shut off; no more gurgle.

As for the return air filter, there is only one; an Aprilaire 2200, biggest filter I've ever seen on a residential HVAC system. It's just before the evaporator coils. It normally only needs changing once a year and I did that on August 10. However, I pulled it and looked it over today and everything looks good, clean, and properly aligned.

It seems very odd to me, too. Since the HVAC system is circulating the air; shouldn't be pulling any in from outside and shouldn't be blowing any out of the house, so I don't understand how it could be changing the pressure. Nor do I understand why the first time this happened was 3 weeks ago; the 6th of this month.

I guess I need to call the ghostbusters, or hunt the gremlins.

 

[brin]

Bird...Just a thought but if you use Tidy Bowl to clean your toilets....maybe the tidy bowl guy got flused and is drowning...:laughing::laughing::laughing::laughing: So Sorry...I could not resist..Will I be punished ? :laughing:

 

[dcyrilc]

Bird...Just a thought but if you use Tidy Bowl to clean your toilets....maybe the tidy bowl guy got flused and is drowning...:laughing::laughing::laughing::laughing: So Sorry...I could not resist..Will I be punished ? :laughing:

Normally I would say yes, but I'm laughing too hard to care right now.:laughing::laughing::laughing::laughing:

 

[Kays Supply]

Just for giggles, the next time it runs and gurgles, pull the filter out of the furnace and see if it changes tune. Does the drain for your kitchen sink go in the wall or into the floor? No other drain makes any sound? Try putting some liquid soap down the drain. See if it blows bubbles when it gurgles.

 

[Bird]

Will you be punished? Well, if that Tidy Bowl guy ever gets out of there and catches you, you might be.:laughing::laughing:

 

[Bird]

Just for giggles, the next time it runs and gurgles, pull the filter out of the furnace and see if it changes tune. Does the drain for your kitchen sink go in the wall or into the floor? No other drain makes any sound? Try putting some liquid soap down the drain. See if it blows bubbles when it gurgles.

I don't think I want to have to go up in the attic and pull that filter. The drain goes into the wall. This is a double sink; small sink with disposal on the left, larger and deeper sink on the right, the dishwasher discharges into the top of disposal, and the condensation drain for the HVAC is PVC down inside the wall, then a rubber hose into the big sink drain, near the top, so of course before the P trap. Incidentally, you can also stop the gurgling simply by putting the stoppers in both sink drains. So I reckon that's the easiest solution.

 

[SandburRanch]

Furnace shut off; no more gurgle.

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With the furnace blower running try temporarily plugging the drain pipe that drains the AC condenser pan and see if that changes anything.

 

[kenstrac]

So if the drain from the A/C goes into that drain and you have not run the unit in cooling mode the water is probably evaporated in the trap on the A/C allowing the air through.

 

[CurlyDave]

Incidentally, you can also stop the gurgling simply by putting the stoppers in both sink drains. So I reckon that's the easiest solution.

That is a huge clue. The air pressure in the house is higher than in the drain line.

Somewhere you have a blower or fan pushing air into the house.

Maybe your furnace, maybe an exhaust fan that is somehow reversed, maybe something else.

 

[ronjhall]

Could be you have a furnace hot air leak in the attic. To make up for lost air, the old air intakes have to draw air from somewhere. Path of least resistance could be your drains.
I would think you would get some smell in the house if that was the case.

 

[Redneck in training]

I would suspect suction duct. The furnace is drawing air from outside pressurizing the house.
In fact you might test which way the air is going in the sink. If you smoke blow smoke on the drain when it gurgles. If the smoke is being sucked in the house has positive pressure. Then inspect suction duct in the attic. If the smoke gets blown away or the gas smells then the house has negative pressure. Inspect discharge ducting in the attic.

 

[Bird]

Well, I'm not even sure it's a pressure problem. I was just in the kitchen getting another cup of coffee, the heat was on, the sink was gurgling, the heat cycled off, and the gurgling stopped. Now the outlet in the ceiling in the kitchen/dining area does allow some air to blow directly into the sink. I just cannot imagine it being enough volume of air, or pressure, to cause that gurgling. And I also cannot understand why this just started happening earlier this month. However, it's only happening when the heat is on; not the cooling (volume of air being moved feels about the same). We had a complete new HVAC system installed in May of this year, so other than very brief testing, the heat wasn't used until this month.

But anyway, I'm just happy to know I don't really have a serious problem.