Why is my kitchen sink draining so slowly?

Why your kitchen sink drains slow

A slow kitchen drain almost always comes down to grease. You pour warm oil and fatty rinse water down the drain, it flows fine while it's hot, then it cools and sticks to the pipe walls a foot or two in.

Over months, that coating narrows a 1.5-inch drain to the width of a pencil. Food particles catch on the grease and it thickens from there.

The good news: this is one of the most DIY-friendly plumbing problems there is. Most people fix it in under an hour with a bucket, a hand auger, and a pair of channel-lock pliers.

The bad news: if you've already dumped chemical cleaner down it, or if more than one drain is slow, the easy fix is off the table and you're into pro territory.

What's actually causing it

in most cases of the time the clog sits in one of two places: the P-trap (the U-shaped pipe under the sink) or the drain arm (the horizontal pipe running from the trap into the wall).

The trap is designed to hold water and catch debris, so it's the first suspect. Pull it and you'll usually find a gray ring of hardened grease and a wad of trapped food.

The drain arm is the sneakier culprit. It runs slightly downhill toward the wall, so debris settles along the bottom. This is where a hand auger earns its keep.

If your kitchen has a garbage disposal, add it to the list. A disposal that isn't grinding fully sends chunks straight into the trap below it.

Less often, the problem is a blocked vent or a clog deep in the main line. Both of those change the whole picture, which is why you check for gurgling and other slow fixtures before you start.

• P-trap: grease ring and trapped food (most common)
• Drain arm: settled debris in the horizontal run
• Garbage disposal: incomplete grinding sends chunks down
• Vent: restricted airflow causes gurgle and slow flow
• Main line: multiple slow fixtures point deeper

How to clear it yourself, step by step

Start under the sink. Clear out the cabinet and put down a towel, because there's always more water in the trap than you expect.

Slide a bucket under the P-trap and loosen both slip nuts. On plastic traps you can usually do this by hand. On metal, wrap the nut with a rag and use channel-lock pliers.

Pull the trap off and dump it into the bucket. Look inside. If you see a grease ring, that's your answer, and it's an easy one.

Scrub the trap with a bottle brush and rinse it in another sink or outside. Check the rubber washers while it's apart and replace any that are cracked (a fresh pack is a couple dollars).

Now run a hand auger into the drain arm toward the wall. Feed it in, crank until you feel resistance give way, then pull it back slowly with the debris.

Reassemble everything, hand-tight plus a quarter turn. Overtightening cracks plastic threads and strips metal ones.

Run hot water for two full minutes. Watch every joint for drips, then re-time the drain against your baseline.

What it costs in 2026

DIY runs $15–$90 in tools and parts. That covers a hand auger, a replacement PVC trap kit if yours is corroded, new washers, and a bottle brush. You keep the auger for next time, so future clears cost almost nothing.

A plumber runs $150–$350 for a kitchen drain clearing in most US markets. That range reflects the trip charge, labor, and sometimes a power auger or a camera inspection if the clog is deep.

The gap between DIY and pro is wide here, which is why this is worth trying yourself first. The physical work is simple and the downside of failing is just calling the plumber you'd have called anyway.

Where the pro price climbs: old galvanized pipe that needs replacement, a clog in the main line, or a vent issue that requires roof access. Those aren't drain-cleaning jobs, they're repairs, and they cost accordingly.

• Hand auger: $20 to $30
• PVC P-trap kit: $8 to $15
• Replacement washers: $2 to $5
• Pro drain clearing: $150–$350
• Disposal replacement (if needed): $200 to $450 installed

When to DIY and when to call

Do it yourself if one basin drains slow, your pipes are PVC or copper, and the clog clears within a few feet of the trap. That's the standard case and it's very manageable.

Call a plumber if the auger won't pass, if the trap is clean but water still crawls, or if the pipe you're touching is corroded galvanized steel that flakes when you handle it.

Also call if more than one fixture is slow. That's a main-line issue, and running an auger from the kitchen won't reach it.

One firm line: if you already poured chemical drain cleaner down the sink and it didn't work, tell the plumber before they open anything. That caustic liquid is still sitting in the trap and it will splash.

Can you wait on this?

A slow drain is low-urgency, so you can put it off a few days without damage. But don't sit on it for weeks.

A drain running slow is already 60 to 80 percent blocked. The last bit closes fast once grease keeps building, and it always seems to happen when the sink is full of dishes.

If you're hosting a big meal or heading into the holidays, clear it beforehand. Turkey fat and potato peels are exactly what pushes a slow drain into a full clog.

The one thing you can't wait on: if you smell sewer gas, hear gurgling in nearby fixtures, or see water backing up instead of draining down. That's a system problem, not a slow drain, and it needs a plumber now.

How your home's age changes things

Homes built before roughly 1960 often have galvanized steel drain pipes. These corrode internally and grow a rough, scaly interior that catches debris no matter how well you clear it. If you're fighting the same slow drain every few months, the pipe itself is the problem.

Homes from the 1970s and later usually have ABS or PVC drains, which stay smooth inside. A slow drain in these homes is almost always just accumulated grease, and clearing it actually fixes it.

Older homes also tend to have shallower trap arm slopes and long horizontal runs to the stack. That gives debris more places to settle, so a hand auger sometimes needs to reach farther than you'd expect.

Keeping it clear for good

The single biggest thing: stop rinsing grease down the drain. Wipe greasy pans with a paper towel before washing, and pour cooking oil into a jar for the trash.

Run cold water when you use the disposal, not hot. Cold keeps fats solid so they get ground and flushed instead of coating the pipe.

Once a month, run hot water for a minute after you've done greasy dishes to move any fresh film along before it hardens.

Clean the P-trap once a year. Now that you've done it once, it's a ten-minute chore that heads off the whole problem.

How we put this together

This guide reflects standard residential drain diagnosis: check the trap first, then the arm, then look upstream and downstream for signs the problem is bigger.

Cost ranges are 2026 US figures covering typical materials and licensed-plumber labor. Your local rates and pipe conditions will shift the numbers, sometimes a lot.

We flag the DIY-to-pro line at the points where a homeowner fix stops being safe or effective: corroded pipe, multiple slow fixtures, chemical cleaner already in the line, and any sign of sewer gas or backup.

When in doubt, a licensed plumber's diagnostic visit is cheaper than a wrong guess that floods your cabinet.