Slow-Draining Bathtub: Possible Causes & Solutions6 min read

Water pooling at your feet when you take a shower? Is your tub taking longer to empty when you pull the plug? You’re likely dealing with a slowly clogging drain. So what do you do?

Clogs created by debris like hair and soap scum are the most likely cause for a slow-draining bathtub. You can unclog the drain using a drain snake or something similar. You can try a plunger as well. Consult a plumber before applying any harsh chemicals.

Don’t call a professional plumber right away. In most cases, you can fix a slow-draining tub with a bit of elbow grease. Let’s look at common causes of clogs and how to prevent them, so that you can decide how to approach your slow-draining tub.

Possible Causes of a Slow-Draining Tub

Slow-draining tubs are frustrating. At its worst, the water can take hours to drain or remain in the tub indefinitely. And if the issue remains unresolved for too long, it may cause damage to your home.

Here are common causes of the clogs that slow down tub drains:

Hair & Other Debris

Some of the main culprits behind clogged drains are hair, debris, and soap scum.

You shed strains of hair when you take a shower or shave. The strands can stick to the sides of the pipes and morph into tangles as they swirl down the drain.

The hair builds up over time and traps water and other materials, preventing them from draining.

Other debris, like dirt and sand carried in from outdoors, also accumulate and clog your shower drain. Masses of soap scum, shampoo residue, and hair care products stick and solidify to the drain pipes as well.

In most cases, the slow drain is caused by a combination of these issues.

Hard Water

Yes, you read that right: water itself can cause issues in your bathtub. Hard water has high levels of calcium, magnesium, and various minerals.

Although you can’t see them, these elements can damage your pipes. Like hair and dirt, the minerals adhere to the sides of the pipes and accumulate over time, eventually causing a blockage.

Clogged Vent Pipes

Vent pipes equalize the air pressure in the drain pipes to prevent a vacuum effect from impacting the drain.

Vent pipes extend through a home’s roof and can be blocked by leaves, twigs, and debris.

In some cases, animals and insects can cause blockages. Clogged vent pipes may be the reason your tub is draining slowly and will need to be dealt with promptly.

How to fix a Slow-Draining Bathtub

Thankfully, removing obstructions from pipes isn’t complicated. The items you can use to unclog the drain are easy to come by and don’t require much effort to use.

Here’s a few simple ways to get your tub draining properly again:

Snake the Drain

Plumbing snakes, aka “drain snakes” like this one (on Amazon) are long metal wires with a spike on one end. The tip rotates by hand or with electricity. If you need to use a drain snake often, look for electric models that work with the press of a button.

When you purchase a drain snake, be sure to consider its length and thickness. 99% of clogs are happening at the drain itself, and will be relatively easy to fix with a small amount of the drain snake.

But if you’re having advanced pipe-clogging issues or you simply have no strainer on the drain in the tub itself, you’ll have to use the drain snake to work your way into the pipe and find the drain.

An advanced clogging issue may require a 25-foot drain snake that’s at least ¼-inch thick. If you live in a multiple-story house, you may need a longer snake with a 50-foot cable.

To snake the drain, gather a pair of safety gloves and a pair of pliers or a screwdriver. Then follow these steps:

  1. Lay down towels around the drain and floor to prevent spills or additional damage.
  2. Take out the drain stopper. You may need to use a screwdriver. Ensure you place the screws in a safe place to avoid losing them inside the pipe.
  3. Insert the end of your plumbing snake inside the drain. Push it inside and twist it clockwise as you move it.
  4. You’ll know you’ve reached the clog when you can’t move the snake anymore. Twist the drain cable counterclockwise and remove the blockage.
  5. Repeat the steps as many times as necessary to clear out all of the debris.
  6. Finally, pour water down the drain to determine if the pipes are clean and working correctly.

If this doesn’t resolve your issue, you may need to call a plumber to finish the job. You can also try pouring hot water down the drain to loosen the debris.

Here’s a great video on how to use a drain snake

Use Homemade Drain Cleaner

You can actually make homemade drain cleaner from just baking soda and vinegar.

When the two ingredients combine, they create a chemical reaction that can free debris and buildup from the insides of your pipes. The homemade solution is fast-acting and less harsh on pipes, your skin, and the environment.

Here’s how to use it:

  1. Wear gloves.
  2. Remove any remaining water inside your tub.
  3. Drop 1 cup of baking soda down the drain. Immediately follow this up with 1 cup of vinegar.
  4. The mixture will begin to froth and bubble. Wait around 10 to 20 minutes until the bubbling stops.
  5. Pour 1 liter of boiling water down the drain to flush it out.
  6. Repeat until your pipes drain smoothly.

Use a Plunger

Cup plungers are excellent tools for flat-surface drains. The design is straightforward is an essential tool for any homeowner.

When you press down, the air is forced down the drain, and pressure builds. Pulling the plunger creates a vacuum and forces anything in the pipe to come out.

Here’s how to unclog a drain using a plunger:

  1. Remove the drain plug cover.
  2. Place the plunger cup over the flat surface of the drain.
  3. If your tub is empty, fill it with water until the plunger cup is submerged.
  4. Grasp the plunger with both hands and pump it for about 30 seconds.
  5. Pour water down the drain to determine if the blockage is clear.
  6. If the water still isn’t flowing, repeat steps as needed.

Clear Clogged Vents

You may have a clogged plumbing vent if you don’t have any luck with the methods above. The vents work in tandem with the drainage pipes to allow old water to move into the sewer system.

Vent pipes can become blocked by bird nests, leaves, twigs, or even small animals.

Here’s how to clear a blocked plumbing vent:

  1. Find the vent. Many vent pipes are located on the roof and stick out a couple of inches. Other houses have vents that end at the attic or on the side of the building.
  2. Use a flashlight to look for blockages.
  3. Clean out any debris with a drain snake or auger. Insert the cord of the tool into the pipe vent until you hit the clog. Twist the cord to hold the blockage and remove it. Repeat this process as needed.
  4. Lower a garden hose into the vent pipe and run the water for 60 seconds.
  5. Turn off the water and wait for a draining “whoosh” sound. If you hear this, the debris is clear and has successfully gone down the drain.

Flush All the Drains at the Same Time

Another effective way to free up debris and blockages is to send a cascade of water down your pipes. You’ll need a several helping hands to use this method.

Here’s what to do:

  1. Plug every drain in your house, including all tubs, showers, and sink drains.
  2. Fill each sink or tub with warm water.
  3. Have someone stand next to each toilet and drain in your home.
  4. Count to three and have everyone flush the toilets and open the drains.
  5. The large amounts of pressure of water flowing in each drain can dislodge clogs and blockages.

How to Prevent Your Tub From Draining Slowly

Clearing a clogged drain is a time-consuming hassle. Fortunately, you can prevent the issue ahead of time instead of using a plunger, plumbing drain, or chemical products.

Here’s how:

Install a Water Softener or Descaler

Water softeners and descalers are excellent for fighting high concentrations of magnesium, calcium, and other minerals in hard water.

Either of these options helps to stop minerals from adhering to the sides of your drain and pipes. Descalers can also enhance the efficiency of your liquid heaters, washing appliances, and faucets.

Water softeners are more expensive to purchase, install, and maintain compared to descalers. However, the option can be well worth it.

Water softeners incorporate salt, which changes the composition of hard water. This not only helps your drains, but speeds up laundry, too.

Keep in mind that you’ll need a qualified plumber to install a water softener or descaler in your home.

Try a Drain Protector or Hair Catcher

Hair, debris, and soap scum are the primary causes of slow-draining tubs. One of the easiest ways to prevent hair and debris from clogging your drain is with a hair catcher.

These devices are constructed to fit standard bathtub drains and catch hair without stopping the flow of water. The TubShroom Drain Protector (on Amazon) is a popular option.

Don’t Forget Routine Maintenance

Lastly, routine inspection and maintenance are one of the easiest ways you can keep your pipes draining smoothly. Professional plumbers can identify any issues and prevent minor flaws from being significant problems.

Most experts have a checklist that includes the following:

  • Looking for symptoms of water damage in the home.
  • Checking the pipes and plumbing system for damage, breakage, or corrosion.
  • Inspecting the toilets to ensure they’re free of leaks and flush correctly.
  • Ensuring the faucets in every room have the correct water pressure and function normally.
  • Searching for clogs or blockages and removing them.
  • Examining the garbage disposal and water heater for signs of damage.
  • Completing a pressure test to detect any minor cracks or leaks in the drains.
  • Cleaning each drain in your home.

Having a professional perform routine maintenance is the simplest way to prevent future issues and stay on top of minor problems.

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Hi, I'm Ed, and I run BuildFanatic! I enjoy providing the best possible information on a range of home improvement topics.

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