Sydneysiders have been flushing jewellery, watches, and other weird items down the household toilet, causing major drain blockages.

In the past three months, Sydney Water crews have had to fix more than 7000 faults in the wastewater network.

Now an advertising campaign has been launched to remind people that pee, poo and toilet paper are the only types of waste that should be flushed.

Sydney Water’s Maryanne Graham said too many “unflushables” are going down the loo and wreaking havoc on the wastewater network.

They include jewellery, watches, notes and coins, kids’ toys such as Lego and figurines, earphones, lighters – and even, on one occasion, a brick.

Other items include wet wipes and oils.

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One in two people are flushing the wrong things down the toilet, Sydney Water estimates.

And three in four are putting the wrong things down the sink.

“The reality is wet wipes, fats, oils and grease and other items like cotton buds, tissues and sanitary products are a major threat to our wastewater network,” Ms Graham said.

Wet wipes are responsible for about 75 per cent of wastewater blockages.

Sydney Water said it spent more than $8 million a year removing 500 tonnes of refuse from the wastewater system.

The ‘It’s Best to Bin It’ campaign highlights what can and can’t be flushed, or tipped into the sink.

Unflushables include wet wipes, cotton buds, tissues, dental floss, hair, cleaning cloths, and sanitary products.

Unsinkables include fats, oils, and grease as well as other kitchen items like coffee grounds and food scraps.