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5 Easy Steps To Fix An Overflowing Toilet

Sep 30, 2020

A newly renovated master bathroom done by romaniuk heating delivering modern plumbing fixtures and installations.

What causes a toilet to overflow?

Toilets are always prone to overflowing. If you notice your toilet not draining properly and starts to overflow, it may be because you may have a clog, plumbing or septic issue. These are the three main areas you want to look at when you notice your toilet overflowing. Here are some of the most common reasons that a toilet will overflow and 5 steps that can help you fix it.

Clogged Drain Line

One of the most common causes of an overflowing toilet is a clogged drain. Drain lines can become clogged due to objects or materials being flushed that are not meant to be flushed. Blocked lines will not allow the water to drain properly. This will cause the water to back up into the bowl and not the tank, in turn causing the toilet to overflow and cause a mess.


If you see the drain lines inside your home are clear, another possible cause can be your sewer lines outside your home. The lines that run outside your home can be just as susceptible to clogs & damages. Foreign objects and root systems from trees in your yard are one of the main causes for your lines to be dislocated or blocked. Other than your toilet overflowing. If you notice water coming into your basement, this can be another warning sign your sewer lines are blocked or damaged.

Septic Tank

Communities that don't have access to the municipal sewage systems, or live in low population density areas will likely have septic tanks. Drain lines from your home will then lead into your septic system that is located underground in your backyard where it will be stored and treated. If your tank is unable to filter the water that's coming in, due to a blockage, it can push the water back into your lines. Which can cause your toilet to overflow.

Low-Flow Toilet

Toilets that are considered low-flow are popular in most households. Growing in popularity these toilets are for the homeowners who are looking to conserve water, save money, and limit their impact on the environment. Newer models of low-flow toilets have improved functionality & options. But till this day they do still have their drawbacks especially in older models. Low-flow toilets are limited on what you're asking the toilet to do. Which can essentially cause your toilet to back up and overflow. Due to the lack of water being used to flush waste down, you're more susceptible to clogged pipes. This plumbing problem is concerning as it not only affects your toilet but also can lead to higher water bills.

Blocked Vent Pipe

If you notice your toilet clogging and overflowing quite frequently, a blocked vent pipe can be the culprit. The way a vent pipe works is that it moves external air into the system to replace the air that is pushed out when you flush. When a vent pipe is blocked, your toilet won’t be able to flush properly, which potentially leads to an overflow. This usually requires skilled professionals to fix. Contact Romaniuk Heating & Air Conditioning if you think your vent pipe might be blocked.

What To Do If Your Toilet Overflows

Turn Off The Water Supply

The first thing you will want to do if you notice your toilet is about to overflow is turn off the water supply. Most of the time water lines attached to the toilet will come with a shut off valve that is located below the toilet tank near the floor.

Raise the Float Cups to Stop Water Flow

If your toilet doesn’t have a shut off valve, there is another step you can take to stop the flow of water. If you remove the tank lid, inside you will find a float that regulates the amount of water that enters your toilet. Raise the float to the top so it will cut off the water that is entering the tank.

Try to identify the clog

Now that you have the water shut off, it’s time to identify what is causing the toilet to overflow. If you notice the issue is coming from the toilet bowl, or where the trap is located then you can use a plunger or snake to break the clog up. When you suspect your issue might be in the drain lines, there are a few things you can look out for. Test your sink faucet by the toilet. If you notice the water in the toilet is rising or bubbling up, that can be a sign your clog is in the drain line. Washing machines are another warning sign to look for. Having the drain line clogged the washing machine will not be able to drain properly and water can back up into the toilet or other fixtures.

What to Keep in Mind

Most clogged drains are fairly simple to fix. Usually the snake, which helps break up the clog or plunger, which will create a vacuum like pressure to free the clog will help resolve the issue If the issue is drain line or septic related there are some things to keep in mind when trying to fix the issue. If you're on a septic system you will want to avoid the use of chemical drain cleaners in the toilet. Chemicals can kill the enzymes in your tank that help break down waste, and can be damaging to the tank itself. Instead you can use hot water to help free the clog, or use septic safe cleaners

Call the pros

If you think the issue might be further in your system or a potential septic issue, it will be time to call in the pro’s. Certified businesses are great in these situations as most of them offer 24-hour emergency services. Romaniuk Heating & Air Conditioning offers emergency plumbing services to the Edmonton & surrounding area.