Grease and oil stick to the pipes. After pouring these substances down your drain they become solid, catching any stray food scraps that come past eventually causing a blockage. Instead, drain the oil into another food wrapper in the bin (for example, chip packets or bread bags).
When flour and water are mixed together, they can turn into a glue-like substance. After coating the edges of your drain, it can collect other bits of garbage and food scraps.
When washing fruit, make sure you take the stickers off. Stray stickers don't disintegrate in water and could cause problems in the future.
Coffee grounds are a common cause of blocked drains. As this plumbing website points out, "Nothing causes more blockages and clogged pipes than coffee grounds and grease." Always dispose of them in the bin or compost.
Products claiming to be 'flushable'
It turns out those flushable wipes can’t actually be put down the drain. In an article published on choice.com.au last year, it was reported that Australia’s water service providers are spending around $15 million a year to clear blockages.