Are gravity filters really effective? Our opinion

Filter tap water without electricity or plumbing connections is possible! This is the whole point of gravity filters. Berkey, British Berkefeld, Pure Filters… These systems appeal due to their ease of use. You simply pour water into a reservoir and let gravity do its work.

But does this simplicity guarantee effective filtration? Not necessarily! Bacteria, pesticides, PFAS, microplastics… Not all gravity filters offer the same performance against pollutants.

Discover our opinion on gravity filters, their advantages and limitations, to choose a filter for tap water that suits your needs.

How does a gravity water filter work?

The operation of a gravity filter is simple. Two tanks are stacked, and water naturally flows from the top one to the bottom one thanks to the force of gravity. All of this without electricity or plumbing connections.

Specifically, here’s how it works:

1. You fill the upper tank with tap water.
2. Drinking water slowly passes through one or more filter cartridges under the effect of gravity.
3. Filtered water is collected in the lower tank and then distributed through a small faucet.
   

But beware, gravity does not filter water on its own! It simply allows it to circulate. It is the cartridges that retain the contaminants.

The latter may contain activated carbon or specific resins. It is precisely their composition that determines the pollutants retained.

What are the advantages and disadvantages of gravity filters?

The advantages of gravity filters

Gravity filters offer several advantages for those seeking a simple and practical solution:

• Without plumbing connection: they are easily installed, without any work.
• Without electricity : no electrical power is required.
• Transportables : you can move them as needed.
• Large capacity : they can hold several liters of water, more than a standard pitcher.
• No water discharge: unlike reverse osmosis, they do not generate wastewater.
  

Despite these advantages, gravity filters also have some limitations.

The disadvantages of gravity filters

While gravity filters have their advantages, they also have disadvantages:

• Slow filtration : several hours for a few liters of filtered water.
• Manual filling : you must regularly add water.
• Stagnant water : bacteria can multiply if the water remains in the tank for too long.
• Bulk : they take up space on the work surface and are often aesthetically unpleasing.
• Regular maintenance : without cleaning or replacing the cartridges, filtration loses effectiveness.
• Variable result : performance depends on the cartridges and can sometimes be difficult to verify.
  

So, are these filters really effective against pollutants?

Do gravity filters eliminate all pollutants?

Gravity filters do not eliminate all pollutants. Their effectiveness depends on the cartridges used and the substances present in the water. One model may be effective against bacteria, but less so against viruses, pesticides, or PFAS.

And that’s where things get complicated. Not all gravity filters offer the same performance.

Do gravity filters retain PFAS?

Some gravity filters retain PFAS present in water. But beware, this does not mean they eliminate them all! Activated carbon, often used in this filtration system, has its limits.

The problem is that it is not easy to know the actual performance of a filter. As explained by Reporterre, manufacturers do not always disclose the exact composition of their cartridges, particularly for reasons of “industrial secrecy”.

So, how do you choose the right water filter against PFAS? By checking test results and certifications. For example, the NSF/ANSI 53 certification certifies the reduction of certain pollutants, such as heavy metals and PFAS. However, some brands, like Berkey, refuse to have their filters certified by NSF and prefer to publish their own tests.

At LaVie, we are transparent. Opropre combines NSF certified coconut activated carbon with WQA (Water Quality Association) certified resin, designed to retain PFAS, including TFA.

Its performance is presented in a scientific report, resulting from work conducted with the Laboratory of Environmental Chemistry (LCE), affiliated with Aix-Marseille University and CNRS.

What does Zone Interdite reveal about gravity filters and microplastics?

Are gravity filters really effective against microplastics? The Zone Interdite broadcast aired on M6 on March 8, 2026 provides some answers.

In this report titled “Our Health at Risk: Revelations about the Plastic that Poisons Us,” independent researcher Jean-Baptiste Fini compared several water filters against microplastics using deliberately contaminated water.

The results, analyzed by an independent laboratory, reveal significant differences between the tested technologies:

• Gravity filter: 30% of microplastics retained.
• Reverse osmosis: 60% of microplastics retained.
• Opropre of LaVie: 75% of retained microplastics.
  

However, these results only concern the models tested in the report. They do not represent the performance of all gravity filters.

On the other hand, they highlight the effectiveness of Opropre, which comes out on top in this comparison with 75% of microplastics retained.

Which solutions to choose instead of a gravity filter?

The gravity filter is not necessarily suitable for all needs. It all depends on the pollutants to be removed and your installation constraints.

At LaVie, we offer two complementary technologies: Opropre, an under-sink filter, and LaVie PURE, a UV-A water purifier.

So, which solution to choose?

• To reduce PFAS, heavy metals, pesticides, and microplastics: Opropre.
• To eliminate bacteria and viruses: LaVie PURE.
• To purify water without altering plumbing: LaVie PURE.
• To filter water directly at the tap: Opropre.
• To remove the cartridges to be replaced: LaVie PURE.
• To operate without electricity or connection to plumbing: the gravity filter.

For a more complete purification, choose the Serenity Pack (Opropre and LaVie PURE). The first reduces pollutants thanks to coconut shell activated carbon and a specific resin. The second complements this action with UV-A, in just 15 minutes.

With the Serenity Pack, you enjoy treated water of quality and healthier at home.