Often when we are called out to blocked drains, customers tell us that they hear gurgling or bubbling noises in the weeks and month leading up the blockage occurring. What the customers don't realise is that this means the drain has been blocked for a while already - they just don't realise it.
A blocked drain doesn't always mean that water is not flowing through the pipes, it instead means that the water flows through at a reduced rate, this leads to air bubbles and gurgling sounds from the drain.
Having a drain that has these partial blockages in multiple places greatly increases the chance of hearing the dreaded gurgling noise in your drain.
Depending on which drain you are hearing the gurgling sound coming, there will likely be different cause to the blockage. If it's your kitchen drain its likely food scraps and cooking oil, if it's your bathroom drain it's more than likely hair oils of your body and soap scum causing the blockage.
Prevention of these blockages is possible however, by ensuring all that you wash down the drain is water and not food scraps etc you will greatly minimise the risk of causing a blockage. If however you already have a blockage it is important to make sure you call a professional plumber to unblock it. Many home remedies such as chemical drain cleaners can do more damage than good.