How To Dispose Of Cooking Oil & Fat

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Understanding how to dispose of waste in your home or business can make a huge difference in avoiding future problems. A common thing people get wrong is cooking oils and fats. So, how should you dispose of cooking oil?

Cooking oil should be disposed of with general waste. Fat solidifies as it cools so must never be poured down the sink or toilet. Allow the oil to cool and scrape all of the grease into the bin once it reaches room temperature.

vegetable cooking oil bottles

Can You Put Cooking Oil Down The Drain?

There is a lot of conflicting information out there on the internet, and a lot of it is incorrect. You’ll find people claiming that they’ve been pouring oil down the sink for years and have never had any problems.

The official line is that oil (cooking or otherwise) should never go down the sink because it can cause blockages. As we mentioned earlier, as oils and fats cool, they get thicker and in many cases solidify.

When fat goes hard, it can quickly stick to the inside of pipes and get stuck in sewers, over time causing the available space in pipes to get narrower and narrower. Eventually, pipes become blocked, and can be incredibly difficult to sort out.

If a waste pip under your sink becomes blocked, you might be able to clear it with a little persistence or disconnecting the U-bend to scrape up the build up of fat. If the blockage is further down the drainage system, it can quickly get very expensive. More on that later.

Can You Pour Cooking Oil Down The Toilet?

Some people believe that it’s fine to pour fat down the toilet. Actually, the same applies – while you might get away with it for years, it is still against the guidance from water and sewage companies, and still gradually clogs up pipes.

You must not pour cooking oil or fat down the toilet, it causes blockages in your waste pipes and even the sewers over time. Put all cooking fats and oils in the normal bin in a suitable container.

What’s more, the water in the toilet is always cold unlike what goes down the sink, meaning the oils and fats will cool and thicken faster, making it more likely that waste pipes will fur up more quickly.

While it may be true that the waste pipe from your toilet is bigger than the one connected to the kitchen sink, it’s nothing compared to the size of the sewers, and even the sewage system gets blocked up from time to time with fatbergs and incorrectly disposed of wipes.

You might have heard that there’s a golden rule with what can be flushed down the toilet, nothing more than the ‘three Ps’. That’s Pee, Poop & Paper. For clarity, by paper it means proper toilet roll, not any other sort of paper, including paper towels.

While we’re on the subject, contrary to some people’s opinions, female sanitary products like towels and tampons must also go in the bin and never down the loo.

Can You Pour Oil Down The Drain With Hot Water?

Another common myth is that it’s OK to send fat down the sink with hot or boiling water.

Cooking fat cannot be poured down the sink, even with hot water. While it is more likely to get further down the waste pipe before hardening when it’s hot, cooking oil still leaves a film in waste pipes each time which gradually builds up to blockages over months and years.

Even if you get lucky and don’t have a blockage problem in your home’s waste pipes, it will still cool in the sewers. Eventually a blockage down there can cause waste to back up – and that could mean your sinks and toilets eventually back up or even overflow. Yuck.

If you accidentally pour fat down the sink it is probably a good idea to use hot or boiling water to help it pass through the system, but it’s certainly much better to dispose of it in the bin in the first place.

What Do You Do With Oil After Deep Frying?

They same principle applies to fat from deep fat fryers as cooking oils, vegetable oils and other fats. Everything should go into the general waste bin.

Allow the fryer to cool down and pour warm fat into a suitable container to dispose of in your regular waste bin. that could be an empty bottle or a tub, and ideally allow it to set as hardened fat will make less of a mess in the bin if it leaks.

A helpful tip is to use a funnel to pour fat into a bottle, such as an empty squash or fizzy drinks bottle. While we’d ideally prefer to recycle those plastics, it’s better to re-use those to house old fat than for it to go down the sink.

Better still, many council’s won’t take plastic tubs like empty ice cream containers (usually plastic group 5). If they’re heading into your general waste bin anyway because your local authority only accept group one and two plastics, then it’s a great solution to dispose of waste fat and keep your bin clean and tidy.

Dealing With Drain Blockages Caused By Fat

When your drains get blocked, you have to foot the bill for resolving the problem. We all take it for granted that you can turn a tap on for water, and pour it away down the sink without giving it another thought for where it goes.

Imagine flushing the toilet and seeing the water level rise and stay there, or emptying our the washing up bowl to see the water just sit there instead of drain away. In most cases you’ll get a bit of warning, slow draining water is a tell tale sign.

As we mentioned earlier, you might be able to resolve the problem yourself if you’re good at DIY by just removing the U bend under the sink – the toilet will almost certainly me more unpleasant to deal with.

If the problem lies further down the system though, or you don’t have the confidence or skills to sort it out yourself, a plumber might be able to fix it for a few hundred pounds. On the other hand, you might need a professional drain unblocking service, and costs can really start to spiral – potentially up towards the thousands of pounds.

Sewer Blockage Responsibility

According to Statistica data, the most common causes of sewer blockages are wipes (over 91%), gravel (over 2%) and female hygiene products (over 2%). Some people have interpreted that to mean that fats and oils are actually not as big of a problem as they’re made out to be.

When you break down the data on wipes though, over 45% of blockages fall into a category of ‘unidentified mass of wipes’. This means that the bulk of the category appears to be wipes, but not enough to fall into the specific baby wipe or surface wipe groups.

In reality, the oil and fat becomes the glue that sticks it all together, and that’s how we get these huge ‘fatbergs’ beneath our road network.

The annual cost in the UK runs into nine figures – that’s over a hundred million pounds clearing up fatbergs alone. It’s a cost that has to be paid for, and you’ll see on your water bill a cost for maintaining the sewers as a separate charge to the water you use.

That’s one of the reasons water companies put so much effort into campaigns to stop people incorrectly flushing waste down the toilet, flushing it down the sink and so on. It really does cause some very unpleasant problems – if not in your own home, further into the waste network, and someone has to clean it up.

While the responsibility for clearing sewer blockages falls on water authorities, we all pay the price for the service on our bills.