The water filter most of us have in our refrigerators and other drinking water systems can make a big different to the quality and purity of the H2O that most of us imbibe.
But although we may appreciate this, many of us don't follow a strict regime of replacing the filter when its time is up. Often, it's a case of guesswork, unless you have latest generation equipment that tells you when it's due.
Here's the thing: If you don’t change your filter when it's due, the very impurities and contaminants that have already been filtered out can leach back into the water.
The main reason for filtering for most of us is to remove the chlorine taste that comes with most city water supplies, but other impurities can include heavy metals and lead; we don’t want them back in our water.
According to the global public health and safety organization NSF, it's not easy to tell when the surface of a filter becomes clogged, so it's important to know when the filter or appliance manufacturer recommends a change. It's important too to install a new cartridge certified by the appliance maker. Using a substitute, even one that seems to fit, can lead to some water bypassing the filtration system.