Now that most households have a dishwasher, rinsing dishes is no longer as common. Even still, tipping the wrong things down the drain can cause your drain to get clogged, leading to serious plumbing problems throughout your Brisbane home. What many homeowners don’t realise is that severe drain blockages don’t just affect your sinks. They can create backpressure that impacts your entire plumbing system, including your hot water system.
Many different items are tipped down the drain without a second thought, but understanding what should and shouldn’t go down your sink is crucial for preventing blockages and protecting all your plumbing systems. In this article, we’ll go through the most common items and whether they can be safely tipped down the drain, plus explain the broader consequences of drain blockages.
What can and cannot go down the drain? (Quick answer)
The short version: your kitchen sink is for water, weak soapy liquids and small amounts of food residue rinsed off plates, and nothing else. As a rule, anything that hardens, swells, congeals or doesn’t dissolve in water belongs in the bin, the compost or a recycling point, not the drain.
| Safe down the sink (with running water) | Never down the sink |
|---|---|
| Cold or warm water | Fats, oils & grease (FOG) |
| Diluted dish soap and weak detergents | Coffee grounds & tea leaves |
| Vinegar | Flour, rice, pasta & other expandable foods |
| Small food residue rinsed off plates | Eggshells, bones & food scraps |
| Diluted ammonia (well flushed with water) | Paint, fertiliser, pesticides & chemicals |
| Baking soda followed by plenty of water | Wet wipes (including “flushable”), plastics & medication |
The detail behind each of these is below, including how to clear a slow drain yourself, and when a blockage is licensed plumbing work here in Queensland.
What should never go down the drain?
- Coffee grounds
- Flour
- Yogurt
- Dairy
- Grease
- Fertiliser
- Paint
- Expandable foods
- Animal droppings
- Eggshells
- Produce Stickers
- Cotton balls
- Medication
- Plastics
- Oils
- Pesticides
- Non-biodegradable products
- Wet wipes
- Chemicals (generally)
- General food scraps (as much as possible)
What can you safely put down the sink?
Many items can be tipped down the sink. Here’s a list of some of the common liquids and solids that can be tipped down the sink.
- Vinegar
- Boiling water
- Ammonia (only when diluted with water)
- Baking soda
As you can see, the list of things that can’t get tipped down the drain is long, and that isn’t everything (although it includes the most common ones). We have seen many Brisbane houses with clogged drains due to tipping the wrong thing down. If you have been tipping any of the listed items down the sink, you should stop. Although it may not have caused an issue so far, you never know when it might. Unfortunately, it’s always at the wrong time that something does go wrong, so you should avoid “taking a chance” wherever possible.
Check out the detailed explanations below if you want to know why you can’t tip some items down the sink?
No. Coffee grounds can still stick to your pipes, causing blockages later on. Because of the myth that coffee grounds “clean pipes”, we frequently get called to houses with blocked pipes due to coffee. It is one of the most common reasons a sink gets clogged. The best way to get rid of coffee grounds is to decompose them in your compost, sprinkle them on your garden or seal them in a bag and put them in the bin.
No. Flour and any substance that expands when wet should not be tipped down the drain. Just think of what happens when you bake something, then leave the mixing bowl out for a few hours before washing it. The flour will be hard to scrape off. You don’t want flour acting as glue in your sink. Scrape flour and other similar substances into a bag before putting it in the bin.
Not really. Dairy products do not clog the drain; however, they can’t be easily broken down, affecting the oxygen level of the waterways. Disposing of dairy products in the sink can thus affect the aquatic life living inside. Every person doing the right thing when disposing of dairy will make a difference. To dispose of dairy correctly, decompose it in the garden.
NO! Grease is the most significant cause of clogged drains that we see. Even if grease is in liquid form, do not tip it down the sink. Grease, as well as other oils and fats, attached solid objects to your pipe. The correct method to dispose of grease is not widely known, leading to many mistakes. To properly dispose of grease or other fats and oils, freeze them in a jar before putting them in the bin.
Can a blocked drain damage your hot water system?
Whilst most people understand that pouring grease and other inappropriate materials down the drain causes blockages, fewer realise that severe drain clogs can actually damage your hot water system. When drains become blocked, water backs up through your plumbing network, affecting not just cold water fixtures but also any appliance connected to your drainage system.
If you’ve had recurring drain blockages and notice your gas hot water system isn’t performing as it should, such as reduced hot water pressure, inconsistent temperatures, or strange noises, the drain issues may have caused collateral damage. In such cases, professional gas hot water systems repair brisbane services can assess and fix any damage caused by drainage problems, ensuring your system operates safely and efficiently.
Your hot water system drains wastewater from showers, washing machines, and sinks. When a major blockage prevents proper drainage, the backpressure can affect hot water system components, slow drainage from hot water taps, and in severe cases, cause damage to hot water pipes and connections. For gas hot water systems specifically, blocked drains can interfere with the condensate drainage line that removes moisture from the system, potentially leading to corrosion or component failure.
The Brisbane Plumbers can address both your drain blockages and any related hot water system issues in a single visit, providing comprehensive plumbing solutions that protect your entire home’s plumbing infrastructure.
Have you been tipping the wrong things down your sink? If so, it might be a good idea to get your pipe checked. We can use the latest CCTV technology to get footage inside your drains. That way, we know if there is a potential problem and can fix it straight away.
Once your pipes have been checked, you can start again from scratch with what you tip down the sink.
How do I clear a slow or blocked kitchen drain?
If your kitchen sink is draining slowly or gurgling, you can safely try a few things yourself before calling a plumber. Work through these in order and stop as soon as the water runs freely again.
- Flush with hot water. Boil the kettle and pour the water down in two or three stages, letting it work for a minute between pours. Boiling water helps soften and shift fresh grease. One caution: if you have plastic (PVC) traps or pipework, or a join that’s recently been solvent-glued, use hot tap water rather than boiling water, because boiling water can soften plastic and weaken a fresh glued joint.
- Try baking soda and vinegar. Tip about half a cup (roughly 100–120 g) of baking soda down the drain, follow with about one cup (250 mL) of white vinegar, leave it to fizz for 10–15 minutes, then flush with hot water. It’s gentle on your pipes and handles light build-up and odours, though it won’t shift a solid blockage.
- Use a plunger. A cup (sink) plunger works well on kitchen sinks. Fill the sink with enough water to cover the plunger cup, block the overflow and any second drain with a wet cloth, then plunge firmly 15–20 times. The seal and suction often free a partial clog.
- Clean the P-trap. The P-trap is the U-shaped pipe under the sink. Put a bucket underneath, unscrew the two collars by hand (or with gentle pliers), and clear out any trapped grease, food or gunk. This is one of the most common spots for a kitchen blockage and is safe for a homeowner to do.
- Run a drain snake. If the trap is clear but it’s still slow, a hand-operated plumber’s snake (drain auger) can reach a blockage further along the pipe. Feed it in gently, turn to break up or hook the clog, then withdraw it and flush with water.
Please skip the caustic chemical drain cleaners. They’re harsh on your pipes (the heat and corrosive action can soften and crack PVC, degrade seals, and damage older metal pipework), and they rarely clear a full blockage. They also leave a tank of dangerous liquid sitting in your trap, which is a hazard if you then need to open the pipe. There are far safer ways to clear a drain.
When should you call a licensed plumber?
If the water still won’t drain after the steps above, if more than one fixture is backing up, if you can smell sewage, or if the blockage keeps coming back, the problem is likely deeper in your drain or sewer line, such as tree roots, a collapsed pipe, or a build-up well past the trap.
In Queensland, repairs to drains, sewer and stormwater pipework are licensed plumbing work and must be carried out by a licensed plumber. It isn’t a DIY job. A licensed plumber can run a CCTV camera down the line to find the exact cause, then clear it properly with a drain machine or high-pressure water jetter. If you’ve got a recurring or stubborn blocked drain, that’s the point to call us.
Why does it matter for the environment and septic systems?
What goes down your sink doesn’t just disappear. It heads into Brisbane’s sewer network or, in some areas, into your own septic system. Getting it right protects more than just your pipes.
- Fats, oils and grease (FOG) cause “fatbergs”. Grease may pour as a liquid, but it cools and congeals inside the sewer, trapping wipes and other debris into solid masses councils call fatbergs. These block public sewers and cost a fortune to clear. Pour cooled fat and oil into a jar or container and bin it instead.
- “Flushable” wipes aren’t. Wet wipes don’t break down like toilet paper. They’re one of the biggest contributors to fatbergs and household blockages, even the ones labelled flushable. Always put wipes in the bin.
- Coffee grounds and eggshells build up. They don’t dissolve. Grounds clump and settle, and eggshell fragments catch on grease and rough pipe walls. Compost them or bin them.
- Septic systems are even less forgiving. A septic tank relies on natural bacteria to break down waste. FOG, harsh chemicals, paint, medication and large amounts of food waste kill off those bacteria, clog the system and can foul the drainage field, leading to expensive repairs and pump-outs. If you’re on septic, keep the sink for water and weak greywater only.
- Trade-waste and chemical rules. Tipping paint, solvents, pesticides and similar chemicals down the sink can breach council trade-waste rules and harm waterways and aquatic life. Most councils run drop-off points for paint, chemicals, and oils, so use them.
Doing the right thing at the sink keeps your own plumbing clear, protects Brisbane’s sewers and looks after the local environment at the same time.
Book an inspection
If you would like to book an inspection in Brisbane, call the Brisbane Plumbers. We are Brisbane’s best emergency plumbers and have the team to handle any job. Our superior equipment and skills allow us to manage these jobs properly, the first time. Call us today on 1300 847 086.
