It may happen that you hear bathtub gurgles when toilet is flushed.
This sound usually takes its origin in the shower, vanity sink, or tub. It can be very annoying or even embarrassing when you have guests around your house.
If you are struggling with this issue, take it easy. Here we offer suggestions for your problem.
Bathtub gurgles when toilet is flushed
There are basically several reasons why you may hear the bathtub drain gurgling when the toilet is flushed. But, before we get to the root of the problem, do you truly comprehend how the plumbing system works?
Typical plumbing systems involves four parts: waste drains, waste vents, potable water, and rainwater management system.
In what follows, we will specifically consider the first two.
Plumbing vent system
Firstly, you may find the reason in the plumbing vent system. The vent pipe is responsible for unobstructed water flow. A clog or a leak in it affects how the water flows.
Each plumbing system is connected to a venting system which brings air out through the roof. In case there is no water in your plumbing pipes, air fills them.
Plumbing systems are designed in a special way, which makes some functions of each drain connected.
When there is a blockage in PVC pipes, the difference between air pressure and water pressure appears, and air gurgles. So in that case, the gurgling noise is air released from the bathtub drain.
Shower and tub drain p-trap
You can also find the matter in the shower drain p-trap. A p-trap is a U-shaped part of your sink which keeps sewer gases from spreading throughout your house.
The toilet bowl doesn’t have the p-trap. This absence is compensated by its inbuilt functions, though. Sometimes a shower doesn’t have a p-trap, or it may be broken or empty.
What does it mean when your bathtub gurgles? There must always be a certain amount of water in the drain pipes. Otherwise, when the toilet is flushed, air pressure on the pipes changes, and the air flows through it, producing a gurgling sound.
If there is a lack of water in the p-trap, sewer gases can get into your house, which is definitely very dangerous.
To check your p-trap, you can use a wire, which you need to insert down into the drain. There should be 4-6 inches of water on the wire. If not, it means drain pipes need to be repaired.
Blocked sewer line
On the whole, a gurgling drain can be a signal that there are blockages on sewer lines. This is a more complicated case, and it requires the assistance of a professional plumber.
How do I stop this gurgling sound?
So now, that we have studied the main causes of the bathtub drain gurgling, you’ll probably ask, “How do I stop my bathtub gurgling?” Follow the next steps.
Plunge your toilet
Some amount of toilet waste inevitably piles up on the pipe walls. We just can’t prevent that. It narrows them and leads to a pressure increase, which results in a gurgling sound.
Plunging your toilet is actually the easiest way to get rid of the gurgling drain, but it will only work if you deal with small obstructions.
How do I plunge the toilet?
You’ll need a toilet plunger with an extension flange. Start with taping the shower drain (airtight) as well as the sink drain and overflow drains shut. Carefully place the plunger over the drain hole and then consistently push and pull the plunger up and down. Flush the toilet.
If you see that gurgling persists, come forward to the following steps.
Use a toilet auger
Sometimes we deal with hardened waste. In that case, just plunging your toilet doesn’t work.
However, you can try using a toilet auger. It has a long arm that allows it to wire deeper than a regular drain auger.
How do I use it?
Close the tub drain and all the sinks with rubber plugs. Remember, there is no need for pushing or pulling the auger wire unless it’s fully folded into the plastic.
Be careful not to scratch your toilet bowl. The auger plastic shaft is curved towards the end in order to prevent it.
If you have a hard clog, you will not manage to do it yourself (even tree roots can become the reason why sewer lines are blocked). There you’ll need professional help to unblock it using a sewer auger.
Clear your roof with plumbing snake
As we said before, the plumbing system is connected to the ventilation system. The role of vent systems is to transfer air out through the roof. Hindrance in the plumbing vent lines can be found in the main vent stack.
How can I clear the venting system?
You should begin by climbing the roof and finding the opening to the vent stack. It usually has a screen (if yours doesn’t have it, we strongly recommend installing it), which can be clogged, so you’ll have to clean it.
Debris may fall from the vent opening and trap stuck in the venting system. Sometimes birds and small animals can climb in these air vents; therefore, you’ll have to clear this out to make the gurgling noises stop.
You can clear your venting system with the help of a garden hose or a sewer auger, aka a plumbing snake. You’ll need to clean all the debris that may cause the obstruction. Sometimes it can be rather complicated, then you need to contact a professional plumber.
In the future, to prevent it, remember to clean the roof vent pipe at least once a year.
Maybe the problem is in your bathtub drain p-trap
If the previous steps didn’t help you, you’d better ask for professional help.
Sometimes your bathtub drain gurgles because it is just old and it has to be changed. That’s why the p-trap may have gotten rusty and started to leak.
To check it, just sniff the tub drain. Of course, it will not have a nice smell, but if the smell is terrible, that means the p-trap can’t hold the water in its dip and that is why it allows the sewer smell to come out of the sewer.
Increase the pipe diameter
Expanding the diameter of bathroom plumbing pipes will be a long-lasting solution. That way all the waste and water will flow freely without producing a gurgling sound.
It may be only done by professional intervention in the plumbing system, but it’s definitely worth the effort.
Install the new pipes
Having old cast-iron pipes won’t do you any good. That is why we strongly recommend you replace it with the new ones. Cast iron is highly susceptible to corrosion.
The corrosion in the pipes leads to sediment accumulation. In such a case, the air pressure will constantly increase when the water flows. Again, this leads to improper venting, which is the reason your bathtub drain makes a gurgling noise.
Obviously, you cannot solve this problem with your own efforts. This procedure involves the help of a professional.
Let’s turn to chemistry
We have one more suggestion on how to solve the problem of gurgling drains. It doesn’t always work effectively, but it is rather quick and easy. So, why don’t you try it? We are talking about a chemical solution.
It can help to clean the tub drain or a shower drain by dissolving the clog. You can use a commercial product, but if you prefer a homemade solution, try this one.
- Pour 1 cup of white vinegar and an equal amount of baking soda into the toilet drain.
- When it begins to fizz, pour approximately 1 gallon of hot water into the toilet.
- The mixture should be fixed for 12 hours. Once the time has elapsed, flush the toilet. You can also plunge the toilet, as it will help to force the mixture down the drain.
- Don’t forget that chemical solutions won’t work if you deal with non-organic materials.
To draw the point
The concern about the gurgling bathtub drain is quite common. It’s not only about an annoying sound, it can be a sign that you need professional help.
In most cases, it is caused by clogged pipes and blocked sewer lines. You can try to solve it by plunging your toilet or using a toilet auger.
Sometimes the matter may be located in the venting system. The clogged vent leads to the disruption of air circulation. In that case, you should try to use a plumbing snake or a garden hose. If there is another reason, you’d better seek a professional plumber.
Sometimes a tub or a shower drain is just old and to be reinstalled. The same with the cast pipes. Taking care of it will be a long-lasting solution to your problem.
Gurgling drains is the side effect caused by the relationship between air and water pressure. If there is no air, a vacuum is formed inside the pipes.
It is essential to take measures to prevent the issue. Make sure no waste is accumulating after your toilet flushes and no detritus is being collected in the ventilation system.
And don’t ignore it when you hear a gurgling noise coming from the bathroom drains. It’s better to take care of it before it causes you a lot of trouble. Wonder how to flush toilet with frozen pipes, read