Toilet Won’t Flush When It Rains (Causes And Fixes)

You might be wondering why your toilet is not flushing as it should when it rains.

It’s not unusual for plumbing problems to arise from time to time, especially if you’ve lived in the same house for a long period. However, if you’re experiencing them more regularly, there may be an external issue that you’re not aware of.

Well, mild to heavy rainfall has been linked to the causes of plumbing issues including overflow and backflow of toilets with no flushing capacity.

In this article, we take a look at various causes of toilets not flushing as a result of rainfall and how to fix the issue.

Rainfall can cause a series of problems that can be responsible for your toilet not flushing properly. These problems include a full septic tank or sewer system, a damaged septic tank, clogged up drains, and cracked sewer pipes.

Full Septic Tank and Clogged up Drains

This is one of the most common causes of plumbing issues like a toilet not flushing when it rains. During rainfall, water can seep into the septic tank and cause it to overflow.

The overflowing tank backflows into the drains of your house through your toilet, bathroom, or any system that drains into the tank.

Also, debris clogs and blocks indoor drains, causing backups. Debris from heavy rain, such as leaves, soil, sticks, and trash, may enter your sewer system and block your drains, causing your plumbing system to back up

For houses connected to the city sewer line, the quantity of rain can exceed the capacity of the drain lines causing the sewer lines to back up. The water can’t travel anywhere else but back up into your house, rather than away from it.

Damaged Septic Tank

Many older septic tanks are built with concrete and are covered by concrete lids that usually fit tightly over them.

However, there might be some structural damage to the septic tank, particularly the concrete lids which can allow for water to enter the septic tanks during rainfall thereby causing an overflow and backflow into your house, particularly the toilet. As a result, the toilet won’t be able to flush properly.

Cracked Sewer Pipe

Another common situation that is responsible for a toilet not flushing after a rainfall is a cracked sewer pipe that connects your house to the city sewer system.

When the rain is particularly strong, your pipes may shift underground. When it’s very rainy outside, the ground around your pipes can soften, allowing them to shift. When you combine this with the increasing pressure in the pipe, your pipes may begin to bend and break, causing significant complications

In this case, rainwater is either flowing into the sewage pipe, causing an overflow, or the pipe is severely compromised, thereby preventing waste from passing through and instead of emptying into the ground, which becomes soggy following heavy rain.

The raw sewage then backs up and overflows into your home’s bottom drains and subsequently your toilet.

To fix your toilet not flushing when it rains, there are a few ways to go about it.

  • You can observe whether the flushing improves once the rain stops for a day or two. A septic tank may not function correctly if the ground is saturated, so waiting until the ground has dried is a smart idea before deciding whether or not you need professional assistance.
woman plunging the toilet
  • Shut off the water supply to the toilet to relieve pressure. Then insert a plunger into the toilet bowl to remove the debris and objects that might clog up the drain pipe and the sewer. You can also make use of liquid septic tank treatment that may aid in the dissolution of solid waste and the prevention of blockages.
  • It is also recommended to call a plumber if the problem doesn’t go away after a day or two. A plumber can analyze the situation and determine whether you need to have your septic tank pumped to remove the water overflow. Also, a plumber may identify damage to your tank or the pipes connected to it and suggest repairs.

Rainfall may wreak havoc on drains, producing blockages and breaks in the system. Whenever you live in a rainy location, it’s critical to have a reliable plumber on your side to assist you if difficulties emerge.

Other Signs Of A Backflowing/Overflowing Septic Tank Or Sewer.

●      Raw Sewage Smell

If there is a drainage backup, your drains may smell foul. A limitation of the free circulation of sewage in your pipes causes an odor. Rather, it becomes stuck in one place for an extended period, emitting a terrible stench that is both annoying and unhealthy to breathe.

Consider how many bacteria are trapped in your pipes and released into your home. Although sewage has a disagreeable odor, permitting unknown bacteria into your home can be deadly.

●      Gurgling Sounds

 As you may be aware, the gurgling sound could indicate a delayed drain. You may have a backup in the main sewage pipe if you detect a toilet gurgling or bubbling while operating a device, such as the washing machine.

When you run the bathroom sink, water backs up into the shower. Even if you hear a tiny gurgling after flushing the toilet, you should be aware that something is wrong.

You might be able to clear the clog yourself if there is one. However, if there is a backup, you may need to contact your plumber

●      Standing Water Around Floor Drains

Floor drains can be found in most basements, laundry rooms, and attached garages. Sewer lines frequently back up into these places before backing up into your toilets if you have these drains.

The presence of water in these drains indicates that wastewater is not flowing freely and is backing up. The flow of water has not been entirely stopped despite the obstruction.

If you discover this problem, you should call a plumber right away because a partial blockade will occur, causing flooding in certain sections of your home

How do I Prevent The Plumbing System Issues When It Rains

●      Consistent Inspection of sewer systems and septic tanks

According to the US Environmental Protection Agency, it is recommended to inspect your septic tank or the sewer system at least every 3 years for septic tank damage or pipe cracks to prevent unexpected backflow into your plumbing system. This might require the help of a professional to ensure a thorough inspection.

be mindful of what you flush down the toilet

●      Be mindful of what you flush down the toilet

There are a lot of items that shouldn’t be flushed down the toilet such as feminine products like pads and tampons, oils and chemicals, baby diapers, etc. They can easily clog the toilet and the plumbing system. So keep in mind what you flush or pour down the toilet.

●      Consider installing a backwater valve.

A valve will help to prevent the backflow of the drain pipe during heavy rainfall and help the flow go in the right direction.

If the city sewers get overloaded during a strong storm, check valves should prevent murky wastewaters from surging through your drainage pipes or into your plumbing fixtures.

●      Consider installing a Sump Pump

This is particularly effective not only in preventing toilet overflow but also in preventing flooding due to stagnant murky water around the drain pipes in each part of the house containing them.

Sump pumps can preserve your home’s foundation in addition to protecting it from flooding and water damage. If the ground around your house becomes too moist, it becomes unstable, and if the weather turns cold enough, the wet soil may freeze and expand on your foundation, cracking it.

A sump pump can aid in keeping the soil beneath your foundation dry and much more stable by removing excess water.

Related Questions

Is It Possible For The Sewer To Back-up Into Other Parts Of The House Apart From The toilet?

All drainage pipes in your home, such as sinks, tubs, showers, and toilets, are most likely connected to the main sewage drain pipe beneath your property. So an overflowing septic tank or an overflowing sewer can back up into any drains that are connected to it.

As a result, there may be stagnant water, poor drainage, and eruption of foul smell in your sinks, tubs, shower, and toilet.

Effects Of Flooding On Plumbing

Flooding has a lot of negative impacts on plumbing and can cause a lot of damage. Because flood water generally contains a lot of silt and debris, it’s normal for exterior drains and inside drains to become clogged.

Fortunately, this can be fixed with the help of professionals who are skilled at performing drain cleaning and hydro jetting to fix this issue.


Mild to the heavy downpour of rain has been implicated in the eruption of issues with the plumbing system ranging from toilet not flushing to stagnant drains in other parts of the house.

While the issues might resolve after a few days, it might be beneficial to call a professional plumber to have a look and make a credible assessment of the situation to suggest the right solution for this problem.

Leave a Comment