Slow Drain in Sink or Tub: DIY Fixes That Actually Work

A slow drain is annoying but rarely an emergency. Before reaching for harsh chemicals or calling a plumber, try these proven DIY methods that actually work without damaging your pipes.

Why Chemical Drain Cleaners Are a Bad Idea

Let’s address this first: chemical drain cleaners like Drano and Liquid-Plumr are not the solution.

Problems with chemical cleaners:

• They damage pipes, especially older metal and PVC
• Heat generated can warp plastic pipes
• Often don’t reach the actual clog (just eat through hair near the drain)
• Dangerous if they don’t work—now you have caustic chemicals sitting in standing water
• Harmful to septic systems
• Create hazardous conditions for plumbers who have to work on your drain

Use mechanical methods first. They’re more effective and won’t damage your plumbing.

Start with the Easy Stuff

Remove Visible Debris

Before anything else:

1. Remove the drain cover or stopper
2. Use a flashlight to look into the drain
3. Pull out any visible hair, soap scum, or debris
4. Use needle-nose pliers or a bent wire for hard-to-reach clumps

This alone solves many slow drains, especially in bathroom sinks and tubs.

The Boiling Water Flush (Kitchen Drains)

For grease-based kitchen clogs:

1. Boil a full kettle of water
2. Pour directly down the drain in 2-3 stages
3. Wait a few seconds between pours
4. Repeat with a second kettle if needed

This melts grease and flushes it through the system. Works best for minor buildup, not major clogs.

Caution: Don’t pour boiling water into a porcelain sink—the thermal shock can crack it. For porcelain, use very hot (not boiling) water.

The Baking Soda and Vinegar Method

This actually works for minor to moderate clogs and helps with odors.

Steps

1. Remove standing water if present (use a cup or sponge)
2. Pour 1/2 cup baking soda directly into the drain
3. Follow with 1/2 cup white vinegar
4. Cover the drain immediately with a wet cloth or drain cover
5. Wait 15-30 minutes as the fizzing action breaks down debris
6. Flush with hot water for 1-2 minutes

The reaction helps break up organic matter and soap scum. It’s not as dramatic as it looks—the fizzing doesn’t create pressure that blasts through clogs—but the alkaline-acid reaction does help dissolve buildup.

Enhanced Version

For tougher clogs:

1. Pour 1/2 cup baking soda, let sit 5 minutes
2. Add 1/2 cup salt
3. Pour 1 cup vinegar
4. Cover and wait 15-30 minutes
5. Flush with boiling water (if pipe material allows)

Plunging: The Most Effective DIY Method

A plunger creates pressure that dislodges clogs. It’s more effective than most people realize.

Sink Plunging Technique

1. Block the overflow hole with a wet rag (the small hole near the rim)—this prevents air escape and maintains pressure
2. Remove the drain stopper if present
3. Add water to cover the plunger cup (2-3 inches)
4. Apply petroleum jelly to the plunger rim for better seal (optional)
5. Position the cup plunger over the drain, ensuring full contact
6. Plunge vigorously 15-20 times with sharp up-and-down motions
7. Pull up sharply on the last stroke to break suction
8. Test the drain
9. Repeat if needed

Bathtub Plunging

1. Remove the drain cover or stopper mechanism
2. Block the overflow plate (usually has screws—stuff a wet rag behind it or tape it)
3. Add a few inches of water
4. Plunge as described above

Cleaning the P-Trap

The P-trap is the curved pipe under your sink. It catches debris and is easy to clean.

Steps

1. Place a bucket directly under the P-trap
2. Loosen the slip nuts on both ends by hand or with pliers
3. Remove the P-trap—water will drain out
4. Clean thoroughly with a bottle brush
5. Inspect for damage (cracks, corrosion)
6. Check for objects stuck inside
7. Reinstall and hand-tighten the slip nuts plus 1/4 turn with pliers
8. Run water to test for leaks

For more on P-trap issues, see our guide on fixing a leaking P-trap.

What You Might Find

• Hair clumps
• Soap chunks
• Jewelry (good news!)
• Food debris
• Mineral buildup

Using a Drain Snake

When plunging and P-trap cleaning don’t work, the clog is further down the line.

Hand-Crank Drain Snake

1. Remove the P-trap or use the clean-out plug if available
2. Feed the snake into the drain pipe
3. Turn the handle clockwise while pushing forward
4. When you hit resistance, continue cranking to either break through or hook the clog
5. Pull back slowly, bringing debris with you
6. Clean the snake and repeat until it moves freely
7. Reassemble the P-trap
8. Run hot water to flush remaining debris

Snaking Through the Drain Opening

If you don’t want to remove the P-trap:

1. Remove the drain stopper
2. Feed a small drain snake down the drain
3. Navigate past the P-trap (you’ll feel it curve)
4. Continue until you hit the clog
5. Crank and pull back repeatedly

Smaller snakes may have trouble navigating the curves, so removing the P-trap gives direct pipe access.

Prevention: Stop Clogs Before They Start

Bathroom Drains

• Use drain covers with fine mesh to catch hair
• Clean drain covers weekly
• Brush hair before showering to reduce loose hair going down the drain
• Don’t shave over an open drain—use a basin

Kitchen Drains

• Never pour grease down the drain—wipe pans with paper towel first
• Run hot water after using the sink
• Use a sink strainer to catch food particles
• Scrape plates into the trash, not the garbage disposal

All Drains

• Flush with hot water weekly
• Monthly enzyme cleaner (like Bio-Clean) keeps pipes clear
• Don’t use “flushable” wipes—they cause clogs
• Be mindful of soap buildup—bar soap causes more residue than liquid

When to Call a Plumber

DIY methods solve most drain issues, but call a professional when:

• Multiple drains are slow simultaneously (main line issue)
• You hear gurgling from other drains
• Water backs up into other fixtures
• Snake goes in but doesn’t find anything
• You’ve tried everything and it’s still slow
• Drain is completely blocked and won’t plunge
• Sewage smell persists

Cost Comparison

Method	Cost	Effectiveness
Plastic drain snake	$3-5	Good for hair near surface
Plunger	$10-15	Excellent for most clogs
Hand-crank snake	$20-40	Great for deeper clogs
Enzyme cleaner	$15-25	Good for maintenance
Plumber visit	$150-300	When DIY fails

Next Steps

If your drain is clear but the P-trap leaks after removing it, see P-Trap Leaking. For toilet-specific drainage issues, check Toilet Won’t Flush Well. Our complete Plumbing Fixes Guide covers comprehensive drain repair and maintenance.