Can You Use Drain Cleaner in a Toilet?

Blocked toilets are a common problem. It’s something that almost all of us will have to deal with at some point and it is pretty unpleasant. Thankfully, a clogged toilet is usually relatively easy to deal with at home.

You might be wondering if reaching for the drain cleaner is the right call. After all, it works for other types of drains. The answer is: no. You shouldn’t use a drain cleaner to unblock your toilet. Let’s take a look at why not.

What is drain cleaner?

Can You Use Drain Cleaner in a Toilet

When people talk about drain cleaners, they usually mean the chemical kind. These are the drain cleaners that you buy in the shops and they can come in a variety of forms but the most common active ingredients will be lye (sodium hydroxide) or sulphuric acid.

The way most chemical drain cleaners work is by creating a chemical reaction when they reach a clog. This reaction is corrosive and causes the clog to break down into smaller pieces so that it will flow away down the pipes.

The difference between a toilet drain and a sink drain

If you look at the back of a chemical drain cleaner, it will often say that it shouldn’t be used in a toilet bowl. And there is a good reason for this.

We asked Rider Drains from Stockton On Tees and they said toilet drains are not the same as other types of drains in your home, such as your kitchen sink, shower, bathroom sink, bath, etc. A clog in your sink will sit just below the opening of the drain. When you pour drain cleaner down, it will interact directly with the clog and work to remove it.

A toilet drain is different, however. It has something called an S-trap. This is a piece of pipe with steep curves in the shape of an S. The trap is designed to prevent odour from coming back through the waste vents and it also keeps the water in the toilet bowl. Toilet clogs won’t be sitting in the toilet bowl. Instead, they will be found past the S-trap.

When you pour chemical drain cleaners into your toilet bowl, the solution will settle in the water but it won’t be able to reach the S-trap. And, therefore, won’t be able to reach the clogs.

With no clog to dissolve, the drain cleaner could instead react with other materials. Potentially, this could cause damage to your pipes. This is especially the case with PVC pipes but even metal pipes can get damaged if they are already showing signs of wear.

If the chemical cleaners do manage to reach the blockage, they may not be effective enough to fully unclog a toilet. Toilet clogs are made up of a larger amount of organic material than you would find in a sink clog. The drain cleaner may reach the clog, and start a chemical reaction, but this reaction may only be enough to punch a hole in the clog.

Once this happens, the rest of the drain cleaner will shoot through the hole, leaving the majority of the clog behind.

Alternatively, the chemical reaction may not be enough to even punch a hole in such a large amount of organic material. If this happens, the chemical reaction will continue in one spot, generating heat, which could cause damage to your pipes.

Are chemical drain cleaners dangerous in a toilet bowl?

drain cleaners dangerous in a toilet bowl

Say you have poured your drain cleaner down the toilet and it hasn’t worked. Now you have harsh toxic chemicals sitting in the toilet bowl.

If you then go in and start using a plunger or other manual methods, these toxic chemicals can easily splash back on you and this can be dangerous to your health. It could also release toxic fumes.

If you use bleach-based bathroom cleaning products, these can interact very dangerously with chemical drain cleaners. Chemical cleaners will often contain ammonia.

Mixed with bleach, this will create chlorine gas. In the worst case, breathing in chlorine gas can be fatal but it can also cause severe burns, difficulty breathing, and extreme irritation of the skin and eyes.

What can I use to unclog a toilet instead of chemical cleaners?

What can I use to unclog a toilet

By far, the most effective method of unblocking a toilet that keeps getting blocked is to use manual removal techniques. The nature of the type of clog, its density, and the configuration of the toilet tank and piping means that manual methods almost always work well.

If the clog is small – homemade drain cleaners

Before you use these manual methods, however, you can try a homemade drain cleaner. This will only really be effective if the clog isn’t fully blocking the pipe. So if you notice the water draining more slowly than usual, but it is still draining, you could try this.

A homemade drain cleaner of baking soda mixed with vinegar can work through small clogs. Even boiling hot water mixed with dish soap can be enough for effective drain cleaning.


A plunger is a go-to method for unclogging a toilet. It works by creating a vacuum over the pipe opening which pulls the clog out, allowing it to be flushed away.

Wire coat hanger

If you can see the clog just beyond the opening, you can try breaking it up with a wire coat hanger. Making it into smaller clogs will allow these to be flushed away.

Drain snake or auger

Drain snakes work on the same principle as a wire coat hanger but they can be pushed much further down the pipes. So if you can’t see the clog, one of these is your best bet.

Calling a professional plumber

If you have tried these home methods and your toilet is still clogged or isn’t draining properly, it is time to bring in a professional. They will understand your plumbing system inside and out and can identify whether there is something else going on. This could be something as simple as a problem with your toilet flapper or something more serious like a problem with the sewer line.

Final thoughts

Most drain cleaners aren’t suitable for use in toilets. Their chemicals can give off toxic fumes, they often aren’t effective at clearing large blockages, and they can cause damage to plumbing systems.

Using manual methods such as a plunger, wire coat hanger, or plumbing snake is much more effective at removing toilet clogs. However if you are tackling the job yourself, make sure to wear rubber gloves and thoroughly disinfect the area afterwards!

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.