There are several reasons why your toilet could be slow draining:

• Low water levels in the tank: A lack of water in the toilet tank is the most common cause of a slow flush. To see if this is the problem, open the toilet lid and check the water level in the tank. If it looks lower than usual, this might explain why there isn’t enough power behind the flush.
• Blockage in the drain: The toilet drain can become clogged with objects including facial wipes, sanitary products, cotton pads, and toys. To check if there’s a blockage, pour a gallon of water into the toilet bowl. If the water rises straight away, then a clog is the culprit.
• Obstruction between the tank and bowl: If a clogged drain isn’t the problem, there could be blockage in the toilet tank. Limescale deposits or other obstructions can form in the inlet hole and cause water to drain into the bowl slowly. Look at the toilet bowl rim when you flush. If there’s no water pouring in or if the flow is slow, this is the most likely cause.
• Defective flush mechanism: A faulty handle mechanism could also be causing water to drain slowly into the toilet. Remove the toilet tank lid and flush. If you notice that the mechanism connected to the handle that opens the flap is malfunctioning, this could be the cause of your slow drain problem.
• Weak flushing system: Sometimes, a flushing system gets weaker over time. This could be as a result of mineral buildup in the tank restricting water flow through the pipes.
• Damaged toilet bowl: A cracked or damaged toilet bowl can also affect the pressure of the flush. The base of the toilet bowl must be airtight to pump water through the drainpipe effectively. You can spot a damaged toilet bowl by inspecting it or if you notice a leak (puddles of water forming around the base).
• Buildup of minerals in the toilet: Another possible cause is an obstruction caused by accumulation of minerals or sediment in the toilet bowl rim. This can block the jet holes which reduces the water pressure of a flush over time.
• Poor ventilation: The cause of your slow flushing toilet may not be centered around the toilet at all. Instead, it might be caused by a blockage in the sewer vent on the outside of the building. We’ll dive into how to check this later.

These are just some of the possible causes for a slow draining toilet, and a few of them are easy fixes that you can perform, while others are more complex and might require a plumber’s attention. In the next section, we’ll take you through how to fix that sluggish toilet.

Once you’ve tested your slow running toilet, it should hopefully be clear whether the problem is with the plumbing, toilet mechanism, or a clog in the system.

Below are tips on what to do if your toilet flushes slow but is not clogged:

1. Take a look inside the toilet tank

If you’ve noticed that there could be a problem with the toilet’s mechanisms, identifying the faulty parts is the first step toward fixing your slow flushing toilet.

Inspect the fill tube inside the toilet tank. This is usually a black rubber tube leading to a wider vertical tube (the overflow tube).

If the fill tube appears to be in good condition, it may simply need to be attached more firmly to the cylinder. If the fill tube appears damaged, replacing it may restore the tank’s ability to transfer water to the bowl effectively. Here’s how to replace the fill tube:

1. Turn off your toilet’s water supply.
2. Remove the tank lid and flush the toilet until all the water drains out.
3. Unscrew the nut connecting the bottom of the fill valve to the water hose.
4. Remove the damaged valve by pulling it up from its base, then insert the new valve.
5. Screw the nut back on to secure the valve.
6. Reattach the refill tube and the water hose, then turn the water supply back on to test the flush function.

Another part that could be malfunctioning is the flapper, which acts as a valve to allow the right amount of water to drain into the bowl. If this is not connected to the toilet plunger or if there’s not enough space for it to function properly, there will be inadequate water in the toilet.

If you’re not comfortable with checking and re-fitting these mechanisms, it’s best to leave it to a professional.

2. Check the toilet bowl for cracks

A leaking toilet can be a sign of a cracked toilet bowl and the cause of a slow draining toilet. Usually, if there’s a crack, it forms within the lower bowl of the toilet, so make sure to examine this area thoroughly.

While a cracked toilet bowl is less common than tank problems, if you discover a crack, the whole toilet will need to be replaced. For a temporary fix, you may be able to apply a sealing agent to the crack, but ultimately a new toilet is the best solution.

3. Clear away mineral buildup

If there’s no identifiable clog, mineral buildup along the toilet rim could be the hidden culprit of your weak flushing toilet. Minerals can gather around the jet holes of your toilet which can lead to a reduction in flush pressure.

To get rid of buildup, apply a mineral removal agent to the jet holes, wait a few minutes, and use a metal tool such as a screwdriver to scrape away the deposits. If you don’t have a mineral remover product, you can also use a solution of baking soda and vinegar (1:2 cup ratio), rinsing the area afterwards with hot water.

4. Make sure that the sewer vent is unblocked

If you’ve tried everything else and there’s still no improvement, it’s time to take things outside. A possible cause for your slow toilet could be a blockage in the sewer line vent, an open pipe that is often found on the roof. This pipe allows fresh air to move through the plumbing system so that water flows downwards.

Sometimes, the sewer line vent pipe can be blocked by leaves, a bird nest, or other objects, restricting the airflow. Common signs of a blocked sewer vent include more than one toilet draining slowly or an unpleasant smell building up inside the house.

To check if there’s a blockage, you need to go onto the roof and inspect the pipe. In some cases, the obstruction may be too far down to dislodge, and you may need to use a flashlight and a toilet snake to unblock it. If you’re not comfortable doing this yourself, calling a plumber is recommended.

If there’s a clog causing your toilet to drain slowly, you need an entirely different approach. The good news is that the methods of fixing a clogged toilet are less technical than those required to fix a broken mechanism. See how to unclog a slow flushing toilet below:

1. Use a plunger or a toilet snake

One of the best ways to banish a clog in a slow draining toilet bowl is by using a plunger or a toilet ‘snake.’ You can buy these items at your local hardware store, and they’re fairly easy to use when you have the right technique.

A plunger works by forcing water in and out of the pipe to dislodge a blockage. Usually, a plunger will help to remove minor clogs in a slow flushing toilet.

A toilet snake or auger is a flexible pipe you put down the toilet drain. This tool allows you to make contact with the blockage and manually break it up to remove it. It’s a little more expensive than your average plunger, but it can be useful for a quick unclogging fix.

2. Use DIY methods

You can also try to clear your slow draining toilet using everyday household products. Popular methods include using liquid dish soap, laundry detergent, or a baking soda and vinegar solution to dislodge blockages. Take a look at our toilet unclogging guide for more information.

3. Use Drano^® for your slow running toilet

If you’re wondering whether there is a Drano product that is safe to use in your toilet - the answer is absolutely. If you have a slow draining toilet, the product we recommend is Drano^® Max Build-Up Remover. It contains microorganisms that break down organic matter in pipes that can slow water flow. As with all drain cleaning products, read safety and usage instructions carefully before using.

You can easily fix a slow flushing toilet with Drano^® Max Build-Up Remover. Here’s how:

• Flush 4 ounces of Drano^® Max Build-Up Remover down the toilet.
• Wait 6-8 hours before flushing the toilet to let the formula work. We recommend using the product before leaving for work or going to bed.
• Repeat steps 1 & 2 for 3 consecutive days.
• Reuse the product on a monthly basis to help prevent further clogs from forming.

For tougher clogs, see our guide on How to Unclog a Toilet.

Sometimes, the best way to fix a slow draining toilet is by leaving it - and letting a professional do the work. If you’re unsure about the inner-workings of a toilet tank, or if you’ve exhausted all your options trying to unclog your toilet, then calling a plumber is your best option.

So there you have it - we hope you found our tips for fixing a slow flushing toilet helpful. Remember that practicing prevention is valuable when it comes to toilet trouble, so treating your toilet with care is key.

Browse our full range of drain-safe, clog-busting products here. For more everyday de-clogging advice, check out the Clog Basics blog for expert knowledge on how to unblock even the toughest obstructions in the bathroom, kitchen and more!