How to Remove Grease From Sink Drain | Melt & Flush Method

A sluggish kitchen drain is almost always grease build-up, and the fix is simpler than reaching for a chemical pour. Softening and flushing the fat out of the pipe works better than trying to dissolve it in place. The sequence below covers what actually clears the pipe on the first try, what to skip, and where to turn if the water still won’t move after a few rounds.

The Step‑by‑Step Grease Removal Sequence

This four‑stage order handles the most common grease clogs without dumping harsh chemicals into your plumbing. Each step builds on the one before it, so work through them in order.

• Remove standing water and debris. Bail out any water sitting in the sink with a cup or small container. Pick out visible food scraps or congealed fat from the drain opening — they block the heat and soap from reaching the real clog downstream.
• Hot water and dish soap. Pour 1–2 tablespoons of dish soap directly into the drain. Follow with very hot or boiling water poured slowly — a full kettle, poured in a steady stream, not all at once. The soap breaks the grease’s surface tension, and the heat liquefies the fat so it can move through the pipe. Let the water drain completely after this step; if it flows freely, you are done.
• Baking soda and vinegar reaction. Pour ½ cup of baking soda into the drain, then follow with ½ cup of white vinegar. The fizzing action physically loosens grease stuck to the pipe walls. Cover the drain opening with a stopper or a wet rag to keep the foam inside the pipe, where it does the work. Let it sit 10–15 minutes, then flush with a full kettle of very hot water. If the water still drains slowly, repeat the baking soda/vinegar round once more before moving on.
• Plunger or drain snake for stubborn clogs. If the water is still pooling, fill the sink with enough hot water to cover the plunger cup (about 2–3 inches). For a double basin sink, seal the second drain opening with a wet rag so the pressure goes straight into the clogged side. Plunge vigorously 10–15 times, checking whether the water starts draining. If plunging fails, insert a plumber’s snake into the drain until you meet resistance, then rotate the handle while pushing through the clog. Flush with hot water after the snake breaks through.

When to Remove the P‑Trap

If the snake still cannot get past the blockage, or if water backs out of the pipe below the sink, the P‑trap itself is probably packed with solid grease. Place a bucket directly under the trap, unscrew the slip nuts at both ends (hand‑tighten them back after), and dump the contents into the bucket. Scrub the inside of the trap with a brush and hot soapy water, then reinstall it and flush the line with a full kettle of hot water. This is also a good moment to check which enzyme drain cleaners safely handle recurring grease build‑up without damaging older pipes.

Common Mistakes That Keep the Clog Stuck

Most failed attempts share one or more of these errors. Checking for them before repeating the whole process saves time.

• Pouring hot water too fast. A rapid dump pushes the water past the clog instead of letting heat linger and soften the fat. A slow, steady stream from the kettle is what liquefies the grease.
• Not sealing the overflow or second sink. A sink plunger needs an airtight seal to generate pressure. Air escaping from the overflow hole or the other basin kills the force — plug both with wet rags or stoppers.
• Stopping after one round. Thick, layered grease often needs two or three heat‑and‑soap rounds before the pipe fully opens. If the water drained a little faster after the first try, repeat the hot water and dish soap step.
• Pouring liquid grease down the drain after clearing it. The clog will return if leftover cooking oil or bacon fat goes into the sink. Let it cool, scrape it into the trash, and the drain stays clear.

FAQs

Can I use boiling water on a PVC drain pipe?

Yes, in moderate amounts. A standard kettle of boiling water (roughly 200°F) is safe for PVC drain pipes rated for hot water discharge. Pour it slowly rather than all at once, and avoid pouring boiling water into a drain that already has standing water — the sudden heat can stress the pipe joint if the water has nowhere to go.

How do I tell if the clog is grease or something solid?

Grease clogs typically cause slow draining rather than total blockage, and the water often gurgles as it struggles past the fat. If the sink is completely stopped with no movement at all, the obstruction is more likely a solid object or a collapsed pipe. Try the snake before the hot water method in that case.

Should I use a chemical drain cleaner if the DIY methods don’t work?

Only as a last resort, because chemical openers can damage the pipe if used repeatedly or mixed with other cleaners. If you have already tried soap, hot water, baking soda/vinegar, and the snake, an enzyme‑based drain cleaner is the gentler choice. Harsh lye or sulfuric acid products should be used strictly per the label directions, and never combined with any other drain product.