3 common water filter mistakes that could put you at risk of a bacterial infection, and what to do instead

• Water filters that come in pitcher form can only do so much.
• You should replace carbon filters every two months, and many don't filter out lead and plastics.
• Faucet filters and household systems can provide you with cleaner water, but they're more expensive.

Many people use filtering pitchers to keep their water clean, cold, and tasting good. In reality, the contraptions work better as vessels for refrigerating water than technologies for removing harmful pollutants.

Your filter only works if you are proactive about changing the filters. And it's important to note that it doesn't filter out everything (though some of the stuff that slips through isn't a big deal).

There are some better long-term options, such as faucet filters and reverse osmosis systems, but they come at a higher price.

Here are the most common mistakes people make with water filters, and why they matter:

You're not replacing your filter every 2 months

The golden rule of water filters is that you have to follow the replacement schedule.

The standard 10- or 11-cup pitchers from Brita and PUR require filter changes every two months (or after 40 gallons for Brita).

Both brands use activated carbon filters made from coconut shells. The technology is capable of removing chlorine, zinc, copper, cadmium and mercury - but other contaminants, like bacteria and viruses, are harder to get rid of.

Germs don't bind to the carbon filter, so they either pass through into your water or get stuck in the filter. Luckily, most tap water has already been treated to remove harmful microorganisms.

But if you don't change your filter frequently, it can become a breeding ground for any bacteria growing inside.

An older German study found that tap water had less bacteria than filtered water after one week, whether it was refrigerated or not. In some cases, the bacteria colony counts in the filtered water was up to 10,000 times those in the tap water.

You're counting on it to remove lead and PFAS

While water filter pitchers are pretty good at removing particles that affect taste, many neglect to take out the contaminants that most affect human health.

The Brita Longlast+ filter is capable of removing 99% of lead in water, but the standard filter is not advertised to reduce lead at all. The same goes for Pur - the Pur Plus filter is certified to remove lead, while its standard model lags behind.

Compared to bacteria, lead is not as consistently removed from tap water in the US. Industrial cities like Pittsburgh, Detroit, and Flint, Michigan, have discovered unsafe levels of lead in their water, which can lead to permanent brain damage in children.

Most water filters are also not certified to remove PFAS, or per- and polyfluoroalkyl substances. These "forever chemicals" are notoriously tough to break down, and they can cause problems for the environment as well as human health.

You haven't considered a more permanent fix

NSF International, a group that tests and certifies water filtration systems, has a list of water treatment products that can reduce PFAS to below the Environmental Protection Agency's health advisory level. However, those products are more expensive and complex than the pitcher you may have in your fridge.

Filtration systems that you attach to your faucet or install under your sink are typically more effective than freestanding pitchers. For example, Pur's faucet filter reduces more than 70 contaminants - more than any other brand or model.

Anything connected to your water line uses a more sophisticated filter, often with a "finer pore structure" to remove more contaminants, Pur's director of technology Mike Mitchell told Popular Science.

Other at-home filter treatments include reverse osmosis and distillation units, which are the most effective but pricier and more complicated than carbon filters.