Fat waste and other common drain blockages
Hot fat poured down the sink can cause blockages as it goes solid in water. Try warming the u-bend gently with a hair-dryer. This should soften the fat for a minute and once the water starts to go down, run the hot tap for two minutes to flush it away.
Did you know that wet wipes, make up wipes, cleaning wipes and baby wipes aren't designed to be flushed? They generally aren't biodegradable which means that unlike loo paper when you flush them down the drain they don't break down and can instead build up in your drains and pipes and cause blockages. Always dispose of wet wipes of any kind in the bin.
Nappies and sanitary products
Nappies and adult sanitary products should not generally be disposed of in the toilet as they can cause blockages. These items should be disposed of well wrapped in the general waste bins.