How to Unblock a Kitchen Sink (Grease & Food Sorted)
Kitchen sinks block differently from bathroom sinks. Where the bathroom's enemy is hair, the kitchen drain's nemesis is grease — and grease blockages have a slow-build character that makes them feel sudden. One day the drain is a bit slow; a few weeks later it's standing water and a dinner party in ninety minutes. The escalation path through five methods covers everything from the quick fix to the "this needs a snake" scenario, in the order that makes sense.
Why Kitchen Drains Block
Every hot pan rinsed in the sink, every oily plate, every drop of cooking fat deposits a thin layer of grease on the pipe wall. At first it coats; over months it accumulates and narrows; eventually it hardens into a layer solid enough to catch food particles, coffee grounds and the odd pasta piece and consolidate into a proper blockage. Unlike a hair clog that sits in the trap, kitchen grease often builds 1–2 metres into the horizontal pipe run — just out of reach of most DIY methods — which is why kitchen blockages tend to be more stubborn than bathroom ones. Full detail on what causes blocked drains.
Method 1: Boiling Water (Start Here)
For a slow kitchen drain (not fully blocked): boil the kettle and pour down the drain in three stages, waiting 15 seconds between each. Hot water re-liquefies congealed fats temporarily, flushing them further down where pipe diameter and flow typically handle them. It's the cheapest, fastest option and it works well on early-stage grease build-up. Repeat weekly as maintenance; a monthly boiling-water flush is one of the most effective kitchen drain habits there is. Note: not suitable for porcelain sinks (use very hot tap water) or older PVC pipe that may soften at prolonged boiling temperatures — hot tap water plus kettle blend works fine.
Method 2: Plunger
For a fully backed-up sink, a cup plunger (flat base, no flange) is correct — the flat surface seals well on a flat sink basin. Block the overflow opening under the rim with a wet cloth first; without this, you're pumping air in a loop. Fill the sink with enough water to cover the plunger cup, seat firmly, and work with slow pushes and sharp pulls — fifteen to twenty strokes, then test. If the blockage is within arm's reach of the drain, this clears it; if it's further down the horizontal run, you've confirmed the fight needs escalating.
Method 3: Baking Soda and Vinegar
Half a cup of baking soda, followed by half a cup of white vinegar, plug the drain, wait 30 minutes, flush with the hottest water available. As our cleaning guide explains, this is a maintenance method rather than a rescue one — it's genuinely useful on the light grease layer before it consolidates, and it deodorises as a side effect. For a full blockage, it's step three in a sequence that may still need the snake.
Method 4: Drain Snake
Feed a hand drain snake 1–2 metres into the pipe and work it through the grease mass with clockwise rotation — grease obstructions typically yield to the corkscrew tip more readily than hair masses. Once you feel the cable travel freely, push through and flush with hot water while the snake is still in place. Remove the snake, flush again. Grease on the cable tip confirms you found the obstruction; clean tip suggests the blockage is further down than a domestic snake reaches.
Method 5: P-Trap Removal (The Big One)
The P-trap — the curved section under the sink — collects whatever the boiling water doesn't flush through. Put a bucket under it, unscrew both slip joints by hand (or with pliers wrapped in cloth to avoid damage), slide the trap off, and whatever is inside explains everything. Clean the trap thoroughly, check the wall pipe immediately downstream, reinstall hand-tight plus a quarter turn, and run the tap. Many kitchen blockages live entirely in this section. While it's off, it's also the moment to decide whether a grease-trap service under a commercial or rental kitchen is overdue — grease traps that haven't been serviced regularly are a professional cleaning job, not a DIY one.
Preventing Kitchen Drain Blockages
The three-rule kitchen drain policy: scrape plates into the bin before washing (food debris belongs there, not in the drain), pour cooled fat and oil into a jar rather than the sink, and run the hot tap for 30 seconds after every greasy wash-up. None of this is heroic, and all of it dramatically extends the interval between blockages. An under-sink grease trap, fitted by a plumber, is worth considering for high-cooking households — it catches what the rules miss.
Kitchen Sink Blocked in Geelong?
Grease blockages that beat the snake usually need hydro jetting — the high-pressure scour that actually cleans the pipe wall rather than punching through. Same-day across Geelong and the Bellarine.
📞 Call 0491 570 006FAQs
How do I unblock a kitchen sink with standing water?
Remove as much standing water as you can with a cup, then plunge with a flat-base plunger (overflow hole blocked first). If plunging fails, try a drain snake. For persistent grease blockages, a plumber with a hydro jetter cleans the pipe properly.
Why does my kitchen sink keep blocking?
Grease and food build-up on the pipe walls is the usual cause — it accumulates over months, then one day traps enough debris to block fully. Regular hot-water flushes, scraping plates before washing, and not pouring fat down the drain are the prevention.
Can I use baking soda and vinegar on a kitchen sink blockage?
For light grease and maintenance, yes. For a full blockage, it helps at the margins but usually needs mechanical clearing as well — baking soda doesn't dissolve solid grease masses.
Should I remove the P-trap to unblock a kitchen sink?
If the plunger and snake haven't cleared it, yes — the P-trap is one of the most common locations for kitchen blockages. Put a bucket under it, unscrew the slip joints and clear whatever is inside.
Related guides: Baking soda and vinegar for drains · Drain snake how to use · Blocked drains Geelong