3 ways to fix poorly draining toilets

3 ways to fix poorly draining toilets
3 ways to fix poorly draining toilets

Did your toilet suddenly start to drain more slowly? It could be the result of many problems, but many of them can be fixed without hiring a plumber. You should start by taking a look at the reservoir, the most common culprit. Otherwise, you should try cleaning the bowl with cleaning products. If yours has heavy deposits, you may need hydrochloric acid.


Method 1 of 3: Check the tank

Fix a Slow Toilet Step 1

Step 1. Find the source of the problem

If the water drains slowly, it could be for two things. Either the bowl does not fill fast enough or it does not empty fast enough. If it's the second, the drain hose is probably clogged and you will need to unclog it. If it doesn't fill up fast enough, you need to take a look at the tank.

Fix a Slow Toilet Step 2

Step 2. Remove the cover

The cistern is the largest part of the toilet, usually where the handle is for flushing the toilet. Place the cover carefully on the floor, as the heavy porcelain it is made of could damage the coating.

Fix a Slow Toilet Step 3

Step 3. Check the chain between the handle and the plug

You should see a piece of plastic or rubber blocking the water outlet at the bottom of the tank. This is the valve. Unless the water is not draining at all, you should see a chain between the flapper and the flush lever.

  • There should be just enough slack to cause the part to clog the water outlet. However, it should also be tight enough to raise the flapper when you flush the toilet.
  • When you flush the toilet, the valve should remain open for a minimum of 2-3 seconds or insufficient water will flow into the bowl.
Fix a Slow Toilet Step 4

Step 4. Adjust the chain if necessary

It's a pretty straightforward step. It should go through a hole at the flush lever. You can easily undo it and install a different link in the lever to adapt the length of the chain. You should give it about an inch of slack.

During this process, you will probably get some water from the tank on your hands. As long as you wash them off after you're done, that's okay with you

Method 2 of 3: Use dish soap and a liquid unblocker

Fix a Slow Toilet Step 5

Step 1. Use boiling water

Pour four liters of boiling water down the toilet. Pour it into a bucket before pouring it into the bowl. It will cleanse the residues that could slow the flow of water when it is evacuated. Leave to act without flushing the toilet.

Fix a Slow Toilet Step 6

Step 2. Pour the unblocker into the bowl

Make sure you are using a product that it is safe to put down the toilet. As a general rule, the directions for use on the package should tell you how much to use.

  • Pay close attention to the instructions. Some of these products are not intended for use on earthenware and others should be used while wearing protective equipment.
  • Always follow the instructions for using the product exactly. For some of them you will have to flush the toilet right away, but for others you will have to wait for them to take effect first.
Fix a Slow Toilet Step 7

Step 3. Add dish soap

Find the overflow pipe in the tank. Usually you will see a smaller pipe inside. You need to put a small amount of dishwashing liquid in it, about a tablespoon.

If you have a calcium-removing product or a lime, you can substitute them for dish soap, they may even be more effective

Fix a Slow Toilet Step 8

Step 4. Leave on for ten minutes

This will give the product enough time to descend into the pipe. In addition, it will release calcium and other deposits on the walls, which will facilitate cleaning.

Fix a Slow Toilet Step 9

Step 5. Flush the toilet

This will allow the water to pass through the pipes to bring it out in the holes under the rim. The washing up liquid should then remove all residues in the tank. The liquid unblocker should also remove clogs and mineral deposits in the pipe, which will improve toilet drainage.

Method 3 of 3: Use hydrochloric acid

Fix a Slow Toilet Step 10

Step 1. Take some safety precautions

Remember to put on gloves, a mask, and eye protection. You should also wear an apron and rubber boots to protect yourself.

You must ventilate the room well by installing a fan at the window to bring the air in and out. If you have an extractor in the bathroom, turn that on too

Fix a Slow Toilet Step 11

Step 2. Turn off the water supply and flush the toilet

Use a sponge to remove any water that remains in the bowl. This will allow you to be sure that the acid will clean the bowl to the bottom, including the siphon. It is a small hole in the bottom of the bowl through which the passage of water is forced to empty the toilet. You will see it working at the end and the deposits there could be responsible for your evacuation problem.

Fix a Slow Toilet Step 12

Step 3. Remove the tank cover

Insert a plastic funnel into the overflow pipe. If there is a fill pipe above, remove it first. The funnel opening should be as wide as possible to facilitate acid flow, but narrow enough to enter the overflow pipe.

  • Do not use a metal funnel, as the acid will corrode it.
  • Rinse it well after use and do not use it in your kitchen.
Fix a Slow Toilet Step 13

Step 4. Carefully pour in the hydrochloric acid

You only need to pour a few tens of milliliters. Pour it fast enough to get it through the holes in the rims of the bowl, but not so fast that the funnel is full, as this acid splash is extremely dangerous.

Pour the rest of the four liters into the bowl, this will also help clean the pipe

Fix a Slow Toilet Step 14

Step 5. Install plastic wrap

Cover the cuvette and reservoir with plastic wrap. Try to seal them as tightly as possible. Only cover the bowl, not the seat. This helps prevent acid fumes from filling your bathroom.

Alternatively, you can also cover the toilet with a transparent garbage bag

Fix a Slow Toilet Step 15

Step 6. Leave on for 24 hours

If you have children or pets, lock the bathroom door. The acid will dissolve the mineral deposits in the bowl and the pipe.

Fix a Slow Toilet Step 16

Step 7. Remove the plastic wrap and flush several times

Do not forget to reopen the water supply. It is recommended to repeat several times if the pipes are made of iron, as prolonged contact with the acid could damage them.

Fix a Slow Toilet Step 17

Step 8. Check the water drainage

Find the holes on the rim of the toilet bowl. This is where the water flows every time you flush. Make sure it flows smoothly each time you operate the lever. You could also use a clothes hanger to check that the holes aren't blocked.

  • If there is no accumulation under the rim of the bowl, you can clean with a bottle brush (which you will not use for the bottle afterwards…).
  • If necessary, repeat the entire procedure.


  • Never mix different chemicals! This could cause a violent reaction which will unexpectedly and uncontrollably project hazardous substances which can cause burns or even blindness, release large amounts of toxic gases or generate heat which will crack the cuvette.
  • If you have small cleaning pads in the tank (the ones that make the water blue), put on rubber gloves and collect them to put them in a plastic bag before flushing again to remove the remains of chemical products.
  • If you clean the toilet bowl with chemicals, you must flush the toilet several times before adding another chemical.
  • If you used a liquid unblocker, flush the toilet several times and wait long enough before adding hydrochloric acid or whatever.
  • The acid could also destroy the valve and other metal parts in the toilet, such as the overflow pipe. If you don't have the knowledge to replace some toilet parts on your own, you should consider using a weaker acid or purchasing a new toilet.

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