6 Reasons Your Bathroom Sink Is Draining Slowly and Potential Solutions
Find out what’s clogging up your sink
Highlights
A clogged pipe is the most common reason for draining issues.
Slow bathroom drains may indicate a larger plumbing issue, such as old pipes.
A plumbing snake, flushing with hot water, or a gentle drain cleaner can often fix the problem.
If DIY solutions don’t work, a plumber can use a camera to look for problems deep within the plumbing system.
Why Your Bathroom Sink Is Draining Slowly
You’ve worked hard to turn your bathroom into the spa-like oasis of your dreams. But maybe you’ve noticed that your bathroom sink is slow to drain. What’s really slowing down your bathroom plumbing, and what can you do about it? Here’s how to identify the causes of slow-draining sinks.
1. Clogged Drain
What causes a slow draining sink? Well, one of the most common culprits is a clog. Fortunately, there are a few pretty simple options for clearing stopped-up drains and pipes.
Simple tools such as a plunger or a handheld drain snake can help you clear the clog, especially if it’s relatively close to the drain. Tread gently, though, and avoid harshly pushing, pulling, or yanking. This could cause the tool to get stuck or break off inside your pipes, as well as break or crack your pipes.
You can pour hot water or a store-bought liquid drain cleaner down your drains to dissolve debris and buildup and potentially remove clogs deeper within your system. Approach this strategy with caution, though, as some drain cleaners contain harsh chemicals that may damage your pipes.
In general, drain cleaners that contain chemicals can be quite caustic and can eat away at your pipes over time, regardless of how new your plumbing is or what material it’s made of. If you use a store-bought drain cleaner, choose ones made from natural, non-corrosive, non-chemical ingredients. Bioenzymatic drain cleaners are usually the best natural drain cleaners that can be purchased over the counter and won’t threaten your pipes.
Using hot water to unclog a bathroom sink can be highly effective, especially in older homes with aging plumbing. But if the water is too hot (i.e., boiling), you may do more harm than good to your system.
2. Hair Buildup
One of the leading causes of clogs in your bathroom drains and pipes is hair buildup. To keep hair in check, flush out your drains with hot water at least once a week and an enzymatic or bacteria-based drain cleaner once a month—or more if you have family members with particularly luxurious locks.
These natural drain cleaners are non-corrosive and will not stress or eat away at your pipes. They also don’t produce harmful fumes or contact hazards, so you can use them regularly without risking either your plumbing or your family’s safety.
You should also clear hair away from drains each time you shower or bathe, and use a hair cap for shower and bathtub drains. If you lean over the sink to groom, be careful that no clippings get washed down the drain. Don’t forget to clean hair out of your sink stopper as well, but if it gets clogged, you can fix a sink stopper with DIY skills.
3. Tree Roots
Trees like to take in a lot of water, and the pipes around your home make for a good source if their roots can find their way inside. How can tree roots grow in the pipes? A few different ways.
If you have an older home built before the 1980s, it’s likely your pipes are made of a material like concrete or clay that can break down easily over time. Pipes can also be accidentally broken during construction or even when the ground freezes. Lastly, pipes under your home may have been installed improperly, allowing trees to find and clog your drain.
Because it’s hard to see what’s happening without digging up your yard, it’s best to hire a pro if you suspect tree roots are causing a drainage issue. A pro can perform a plumbing inspection, send a camera down the plumbing to diagnose any breaks, and recommend any necessary maintenance or repairs.
4. Stuck Objects
Things fall into sink drains—small toys, contact lenses, bobby pins—it happens. But these objects, if left in place, can cause further clogs as they attract debris buildup around them. If you know what fell down the sink, like a ring, you can try to use wire or a coat hanger to retrieve it. If you know something fell down the drain recently, but you’re unsure what it is, you can try to use a shop vacuum with a sock or nylon pantyhose over the vacuum nozzle and suck up the small object. However, this doesn’t always work, and you may need to call a plumber to retrieve the object. Just make sure to keep your sink’s water off so that the object doesn’t move farther down the pipe.
5. Vent Pipe Issues
A vent pipe, or an air admittance valve, is usually installed and connects to your sink drain pipe. The vent pipe allows air into the sink’s drain pipe to balance the displaced air when water runs down the drain. It works by sucking air into the pipe when there is negative pressure, and closes when the pressure turns positive.
If your vent pipe is blocked, say by debris in the pipe, it won’t allow air to flow properly. This means water won’t move through the pipes fully because the air isn’t there to push it along. You can try to open and close the valve; if it’s stuck, something may be lodged in the valve. You can also check if there’s water leaking from the valve, which may signal it’s damaged.
If air can’t get into your pipes, you’ll likely need to replace the valve.
6. Old or Corroding Plumbing
Sometimes, it’s not a clog that’s causing the problem but issues in the system itself. As noted above, certain types of pipes in homes built before the 1980s have a greater chance of breaking down because they’re made of materials like wood pulp fibers, cement, or even cast iron. Over time, these materials break down and make it difficult for water to flow properly. While it will likely be a bigger issue throughout your house, it will absolutely contribute to a slow-draining bathroom sink.
4 DIY Solutions for a Slow-Draining Bathroom Sink
If you’re a handy DIYer, you may be able to figure out how to unclog a bathroom sink and get it draining correctly. Roll up your sleeves and check out these possible solutions.
Clear Out Debris
You can clear out the debris in your pipes using a wire hanger, a zip tool, or a drain snake. A zip tool or a snake is going to be easier to use, but in a pinch, you can straighten out a wire hanger instead. Just be sure to wear gloves when handling your hanger so you don’t accidentally injure yourself.
Use Homemade Drain Cleaner
You can try homemade solutions using things that are probably already in your pantry. To start off, you can pour a 1/2 gallon of boiling water down the drain if you have metal pipes, but avoid doing this with plastic pipes. If that doesn’t work, you can learn how to unclog a drain with baking soda. Pour a 1/2 cup of baking soda down the drain, and follow this up with a 1/2 cup of white vinegar. Wait an hour before flushing the drain with hot water.
Clean the P-trap
Since P-traps are supposed to catch extra debris, it’s necessary to clean them out periodically. Turn off the water, place a bucket underneath your P-trap, and use a wrench to remove the P-trap. Pour out any contents into the bucket and use a brush to clear the pipe.
Use a Liquid Drain Cleaner
When every other DIY option has failed, you can head to the store and grab a chemical liquid drain cleaner. Follow the manufacturer’s directions, which typically involve pouring the liquid down the drain, waiting for 15 minutes, and then flushing the pipes with hot water.
Tips to Prevent Slow-Draining Bathroom Sinks
Knowing what causes bathroom sinks to clog will help you prevent a slow-draining bathroom sink. Moreover, learning how to clean a sink drain and maintain it regularly will help keep it functioning. In addition to regular cleaning, here are some other practical things you can do:
Brush your hair away from the sink
Clean the sink stopper weekly
Install a sink grate
Flush your sink with hot water from the faucet
Avoid dropping toothpaste down the drain
Regularly clean your drain if you shave over the sink
When to Call a Professional to Unclog a Sink
If you’ve tried to fix the slow drain in your bathroom sink and nothing is working, it may be time to call a local plumbing professional. Not only can a plumber clean out your drains effectively without risking damage to the system, but they can also inspect your plumbing and alert you to existing or potential problems.
If you have a stubborn clog and you call in a pro, drain cleaning costs are $240 on average.
On the other hand, if you’re looking to maintain your system and prevent future issues by having your plumbing lines inspected and cleaned, you’re likely to pay around $150 per hour. Before you pay for a drain cleaning service, you need to know what to look for, including the documentation you’ll need to ensure the service is reputable and effective.