Every Perth kitchen produces grease. Bacon fat, cooking oil, butter, meat drippings, cream sauces. Most of it ends up down the kitchen sink without a second thought. Here’s why that matters and what you can do about it.
What Grease and Fat Do to Your Drains
When grease enters your drain pipes in liquid form, it cools quickly and solidifies against the pipe walls. That solidified grease catches food particles, soap residue, and other food debris passing through, creating a buildup that grows thicker with every meal. Over time, that buildup will restrict water flow, produce foul odours, and eventually cause severe blockages that lead to sewage overflows, damaged pipes, and costly repairs.
At Proud Plumbing & Gas, we clear grease clogged drains across Perth every week. The cause is almost always the same: years of cooking grease going down the sink, one pan at a time. This guide explains exactly how grease destroys your drainage system, why the common fixes don’t work, and what actually keeps your drains clear long-term.
How Grease Builds Up Inside Your Pipes
A single pour of cooking oil won’t block a drain overnight. The damage is cumulative, and it follows the same pattern in almost every Perth home we visit.
It Cools, It Sticks, It Hardens
The moment hot grease hits your drain pipes, it starts losing temperature. By the time it reaches the horizontal pipe run under your floor or yard, the grease cools enough to thicken and coat the pipe walls. Animal fats like bacon grease, lard, and butter solidify completely at room temperature. Cooking oils like olive oil, vegetable oil, and coconut oil stay semi-liquid but leave a sticky film that acts like flypaper for everything else flowing through.
Each time you wash a greasy pan, another thin layer is added. That layer will trap food particles, soap scum, and food scraps that would otherwise pass through. Week after week, the inside diameter of the pipe shrinks. What started as a 100mm opening might be down to 30mm before you notice anything wrong.
The Chemical Reaction Most People Don’t Know About
Here’s where it gets worse. When fatty acids from cooking grease react with calcium and other minerals in Perth’s water supply, they form a hard, calcium-based deposit that plumbers call a fatberg. Unlike soft grease buildup that you might theoretically flush with hot water, these calcified masses bond to the pipe walls like concrete. They won’t dissolve with dish soap, baking soda, or chemical drain cleaners. They need to be physically cut out of the pipe with professional equipment.
This is why grease blockages are so much harder to clear than other types of clogged drains. The grease build up isn’t just sitting in the pipe. It has chemically bonded to it. Left unchecked, these deposits can also damage pipes from the inside out as trapped moisture corrodes fittings and weakens joints.
What Happens When the Pipe Finally Blocks
Once grease builds up to a critical point, the problems escalate fast. First, you’ll notice slow draining sinks and gurgling noises when the water runs. Then the unpleasant smells start as bacteria breed in the stagnant water sitting behind the blockage. Eventually, the drain becomes completely blocked and water has nowhere to go.
In serious cases, the pressure behind a grease blockage can cause:
- Sewage overflows through floor drains and toilets
- Cracked or burst pipes from constant pressure build up
- Water damage to flooring, cabinetry, and walls
When a grease clogged drain reaches this point, you’re dealing with an emergency plumbing situation, not a simple clogged sink.
The Kitchen Culprits That Cause the Most Damage
Not all fats are equally destructive, but the worst offenders are things Perth households use daily.
Animal fats cause the most drain blockages by far. Bacon grease, the fat you drain off mince, chicken skin drippings, butter, and lard all solidify hard at room temperature. These fats form the core of almost every stubborn blockage we clear from kitchen drain pipes.
Cooking oil is less obvious but still damaging. Vegetable oil, canola oil, olive oil, and coconut oil coat the inside of pipes with a sticky residue that catches food debris and builds up steadily. Coconut oil is particularly bad because it solidifies below 24 degrees, which covers most of the year inside a Perth drain pipe.
Dairy products are another one people overlook. Cream, cheese sauces, yoghurt, and gravy all contain fats that behave the same way inside your plumbing system. Gravy is especially bad because it combines animal fat with starch, creating a paste that hardens when it cools and causes some of the most stubborn clogs we see.
Grease Blocking Your Drains? Don’t Wait
A partial blockage that costs a few hundred dollars to clear can become a full sewage backup that damages flooring, cabinetry, and electrical work. Get it sorted before it gets worse.
Why Hot Water, Baking Soda, and Drain Cleaners Don’t Work
When homeowners attempt to deal with a slow or blocked drain, they almost always reach for one of three things: boiling water, baking soda, or chemical drain cleaners. None of them solve a grease problem, and some make it worse.
Boiling Water and Hot Water
Pouring boiling hot water down the sink will melt grease back into liquid form temporarily. But all it does is push the grease further down the pipe before it cools and re-solidifies. Instead of the buildup sitting directly under your sink trap, it coats the pipe two or three metres further along where it’s harder to reach. You haven’t cleared the blockage. You’ve relocated it.
Hot water after washing dishes can help move small traces of grease, but it is not a solution for existing grease buildup.
Baking Soda and Vinegar
The baking soda and vinegar method is all over the internet, and it makes for a satisfying fizz. But the chemical reaction between baking soda and vinegar produces carbon dioxide gas and salt water. Neither of those has any meaningful effect on hardened grease or calcified fat deposits bonded to pipe walls. It might shift a very light surface layer, but it won’t touch the stubborn blockages that actually cause drain problems. These are temporary fixes at best.
Chemical Drain Cleaners
Most store-bought drain cleaners are formulated to dissolve hair and soap, not solidified grease. The products that are strong enough to attack grease (typically caustic soda based) use harsh chemicals that can also damage PVC pipes and corrode metal fittings. Using them repeatedly weakens your drainage system and still won’t remove the calcified buildup. Improper disposal of these chemicals also creates problems for water treatment processes downstream.
The only reliable way to clear clogs caused by grease is professional drain cleaning. A high-pressure water jetter feeds a specialised nozzle into the pipe and blasts the buildup off the walls at pressures that cut through even hardened fatberg deposits without damaging the pipe itself. A CCTV drain inspection shows exactly where the grease buildup sits and confirms the line is fully clear once the jetting is done.
How to Prevent Grease From Blocking Your Drains
You can significantly reduce the risk of grease blockages and avoid costly repairs by changing a few kitchen habits. None of this is complicated, but it does require breaking the autopilot routine of rinsing everything straight into the sink.
Stop pouring grease down the drain. This is the single most important change. After cooking, let fat cool in the pan, scrape it into a disposable container like an old jar or takeaway tub, and put it in the bin. For larger amounts of used cooking oil from deep frying, pour it into a sealable bottle once it’s cooled and dispose of it with your general waste. Proper grease disposal is the foundation of keeping your drains clear.
Wipe pans and plates before washing. Use paper towels to wipe grease and fat residue off cookware before it goes in the sink or dishwasher. This takes five seconds per item and removes the bulk of the grease before water touches it. It’s the most effective daily habit for preventing grease from entering your plumbing system.
Use a sink strainer. A cheap mesh strainer over your plughole will catch debris, food scraps, and solid particles that would otherwise stick to grease already coating your pipes. Clean it out after every wash-up.
Scrape plates into the bin. Food waste, sauces, and gravy should go in the rubbish, not down the drain. Get into the habit of scraping before stacking, whether you’re washing dishes by hand or loading the dishwasher.
Run cold water after washing dishes. This sounds counterintuitive, but cold water keeps any residual grease solid so it passes through as particles rather than coating the pipe walls as a liquid film.
Consider grease traps for heavy use. If your household does a lot of cooking with oil and fat, grease traps installed under the kitchen sink catch FOG before it enters your drain pipes. They’re common in commercial kitchens but increasingly popular in busy residential kitchens too.
When to Call a Plumber for a Grease Blocked Drain
If your kitchen sink is already showing signs of trouble, including slow draining sinks, gurgling noises, foul odours, or overflowing drains, the grease buildup is already significant and household methods won’t clear it. When your drain is blocked by grease, you need professional drain cleaning.
Don’t wait until your drain is blocked completely. A partial blockage that costs a few hundred dollars to clear can become a full sewage backup that damages flooring, cabinetry, and electrical work. Recurring blockages are a sign that the grease buildup is deep in the line and needs proper jetting, not another round of temporary fixes.
Call Proud Plumbing & Gas for Blocked Drains in Perth
If grease has already done its damage and your kitchen drain is struggling, we can have a licensed plumber on site fast with a camera and jetter to sort it properly.
Call Proud Plumbing & Gas on (08) 6185 3008 for blocked drain clearing across Perth, 24/7, with a $0 call-out fee during business hours and upfront pricing. We’ll show you exactly what’s happening inside your clogged pipes and clear the line the same day, so you can get back to properly disposing of that bacon grease instead of sending it down the sink.
