Quick Answer:
If a drain is getting slower over days or weeks, grease and soft debris are likely building up. Start by tracking how the flow changes, try safe, simple cleanings, and inspect the trap. If the problem keeps getting worse despite basic steps, call a plumber.
Why This Happens
Kitchen drains slow gradually because fat, oil and grease stick to pipe walls. Over time, bits of food and soap make the layer thicker until water can only pass slowly. Other causes include hair, foreign objects, or a partial blockage further in the line. If you’ve cleaned recently and it keeps returning, click that pattern—this can point to recurring grease or an upstream clog. One pattern to watch for is Grease buildup returns after cleaning, which often means grease is still entering the drain or the cleaning did not reach the full clog.
Step-by-Step What to Do
Step 1 — Track the slowdown
- Measure drain speed at the same times for several days. Note morning vs evening performance and after heavy use.
- Record how long it takes for the sink to empty from a set volume (for example, a quart of water). Tracking drain speed changes over several days helps tell if the problem is steadily worsening.
Step 2 — Try the simplest fixes
- Run very hot tap water with a squirt of dish soap for a minute to loosen grease. Do not pour boiling water if you have PVC nearby; use hot water from the tap.
- Use a sink plunger on the slow drain (seal overflow if present) for several good plunges.
- Try an enzyme drain cleaner overnight if grease is likely; these are safe for pipes and work slowly on organic buildup.
Step 3 — Clean the P-trap
- Place a bucket under the trap, loosen the slip nuts, remove the trap and empty contents into the bucket. Clean with gloves and a brush.
- Inspect for grease, hair or foreign objects. Reassemble carefully, checking for leaks.
Step 4 — Use a small drain auger if needed
- If the trap is clear but the drain remains slow, feed a hand auger down the drain to break up or pull out a clog.
- Work gently to avoid scratching or damaging older pipes.
Step 5 — Prevent recurrence
- Don’t pour grease down the drain. Collect grease in a jar and throw it away once solid.
- Install a sink strainer to catch food and run hot soapy water after greasy use.
- Monitor patterns. If you notice the sink is particularly sluggish at certain times, like after overnight settling, it could point to specific causes—see notes on timing like Kitchen sink slow only in morning.
What Not to Do
- Do not delay addressing gradual slowdowns. A slow drain that gets worse is often easier and cheaper to fix early.
- Do not mix chemical drain cleaners with other products or use them immediately after attempting mechanical cleaning—the reactions can be hazardous.
- Do not force tools or use the wrong snake size; this can damage pipes or push the clog farther down.
When to Call a Professional
- Multiple drains are slow at the same time, which may indicate a main line problem.
- Water backs up into other fixtures, or you have repeated clogs after cleaning.
- You detect sewage smell, persistent gurgling noises, or you’re uncomfortable disassembling plumbing components.
Safety Notes
- Wear gloves and eye protection when handling debris or tools.
- Ventilate the area if you use any chemical or enzyme cleaner.
- Do not combine chemical cleaners. If you’ve used a chemical cleaner recently, wait and flush the line well before using a snake or working on the trap.
- Turn off water supply or stop using the fixture while working on the plumbing to avoid spills and surprises.
Common Homeowner Questions
- How long should I track the drain before acting? Track for several days, noting any patterns, then try the simple fixes the next day.
- Will boiling water clear grease? Hot water and dish soap can help soften light grease, but heavy buildup may need mechanical cleaning.
- Are chemical drain cleaners safe? They can damage pipes and pose hazards; prefer mechanical cleaning or enzyme products for recurring grease.