There’s a fringe possibility that your vent pipe is clear and all of your drains are gurgling because your city’s sewer system is blocked.

The water flowing back out elsewhere means the blockage is deeper than the point where your toilet drain and the tub or sink drain meet up with the main drain line or the vent stack is clogged and the water can’t flow correctly. If your home has a septic tank, that could be the culprit instead of the main drain line.

Expect to pay as little as $200 for a tank emptying or roughly $1,700 to repair a damaged tank.

If you don’t have a septic tank, your water is hooked up to your city’s water lines. The fact that more than one home is having issues means the problem has to be the main drain.

FYI, toilet plungers have a flange on the bottom of the bowl. The plungers that are flat at the bottom are designed for sinks.

Your drain goes deeper than your basement, so use an auger that can go that far. If you’re on the first floor, you probably only need 15–20 feet (4. 6–6. 1 m). For a third-floor bathroom or higher, you may need an auger that’s up to 100–150 feet (30–46 m) long. There are electrical drain augers out there, but they’re meant for professional plumbers. You don’t need a $100+ snake to do this.

This is more likely to be the case if your home is especially old and the pipes haven’t been worked on in a long time.

If you still can’t get your toilet to stop bubbling, either check your vent stack or call a plumber.

Without air coming into the system, the air that’s already in your pipes has nowhere to go. This increases the pressure in the entire system and increases the odds of a burst pipe. Your vent stack is the 3–6 in (7. 6–15. 2 cm) wide pipe that sticks up from your roof and points straight up. Your home may have multiple stacks.

Don’t worry—you won’t damage the pipe by doing this. Plumbing pipes can handle the super-hot water from your shower, after all. You may need to do this multiple times to fully thaw the pipe.

If you can’t reach it with an unwound wire hanger, you can use a long stick or something of the sort. If it’s too far down for you to reach, don’t worry. There’s another solution.