Home Blog Buyer's Guides How Do Gravity-Fed Water Filters Work?

How Do Gravity-Fed Water Filters Work?

Dr. Jonathan Doyle - Updated November 04, 2021
Have you ever wondered if clean water is clean? Although, according to the U.S. Environmental Protection Agency (EPA), there are over 80 contaminants that pose a health risk in drinking water. Nevertheless, these chemicals and metals are still present in drinking water due to exposure over time or ingestion from dirty pipes. Furthermore, perfluorinated compound (PFOA) pesticides are emerging new threats present in harmful levels, especially outdoors, like national parks and hiking trails. Therefore, your breakfast cereal could contain these contaminants if you eat foods prepared outside.

What Are Gravity Water Filters?

One of the earliest developed water filtration systems is a gravity water filter. Evidence dating back thousands of years indicates that ancient people utilized the power of gravity in simple sand filters to filter the water.
Recent times have seen the emergence of modern water filters. Ceramic filters were the first modern filters created nearly 200 years ago. Due to its effectiveness, to this day, there have been few changes to the gravity filter.
Sometimes, you may find yourself in unfortunate situations where there is insufficient quality tap water or face an emergency without water or live in an area with problems in the water supply. Fortunately, gravity filters can help in these situations. The significant importance of gravity filters is that they work without electricity; all they need is gravity.

How Does A Gravity Water Filter Work?

Gravity filters have two chambers – one on the other. When using a gravity filter, water poured in the upper filter travels into the lower chamber through a filter. This process uses only the force of gravity. Generally, the lower chamber has a small dispenser that requires switching on to dispense clean water into a drinking glass.
Gravity filtration systems work by exploiting the universal law of gravitation.
Water purification in gravity filters uses the force of gravity. Water runs from the upper chamber, through filter elements, then to the lower chamber. The filter elements consist of millions of microscopic pores that trap impurities to allow only water molecules to pass through.

What Are the Types of Gravity-Fed Water Filtration Systems?

Various kinds of water filtration systems come in variations, and gravity filters are not an exception. Every type of gravity filter has its purpose and advantage. The types of gravity water filters include;


Countertop gravity-fed water filter is usually made from stainless steel, and it sits on surfaces like a kitchen countertop. Usually, the best countertop gravity water filters are available in a range of sizes, with the large sizes having the capacity to filter several gallons of water at once.

Gravity Bag Water Filters

A gravity bag water filter is also known as a gravity water bag filter backpacking. This filter is an on-the-go filtration unit, and it is excellent for people who love traveling from place to place. Ideally, you can't take huge, heavy water filters along with you when hiking or camping. Therefore, a big bag filter is essential, especially when your water supply is depleting.

Ceramic Gravity Water Filter

A ceramic gravity water filter is ideal for people with allergies and sensitivities to chemicals. Ideally, drinking water should not contain excessive chemicals.
This water filter works like a steel water filter unit. All you need to do to get the system running is pour water into the top ceramic chamber.

Waterdrop King Tank vs Berkey Water Filter

It is understandable if you have challenges choosing the best water filter system for your home with several options to choose from. It is even more challenging to choose between the Berkey water filter and Waterdrop King Tank, considering both are stainless-steel gravity-fed water filters with similar exteriors.
The 2.25-gallon capacity of the Berkey makes it the ideal option for medium-sized families. However, customers who prefer a better filtration performance for less opt for the Waterdrop King Tank.
This guide compares Waterdrop vs. Berkey water filters, with emphasis on their similarities, and of course, differences.

Comparison Chart

Waterdrop King Tank
Waterdrop King Tank
Big Berkey
Big Berkey
  • Holding Capacity: 2.25 gallons
  • Material: 304 Food-Grade Stainless Steel
  • Filter Life: 6,000 gallons
  • Water Level Spigot: Included
  • Stainless Steel Stand: Included
  • Wrench: Included
  • System Price: $249
  • Holding Capacity: 2.25 gallons
  • Material: 304 Stainless Steel
  • Filter Life: 6,000 gallons
  • Water Level Spigot: Shop Separately ($41.80)
  • Stainless Steel Stand: Shop Separately ($46.45)
  • Wrench: Excluded
  • System Price: $332

Waterdrop King Tank Gravity-Fed Water Filter

Waterdrop gravity-fed water filter for outdoor use
The Waterdrop King Tank gravity-fed water filter is designed to meet your outdoor and indoor drinking water requirements effectively. With its in-depth drawing technique, customers can expect a better filtration performance. It also has a coconut shell-activated carbon as the natural filter media, providing up to 98% initial fluorine reduction and 98.95% chlorine reduction.
The filtration process also reduces heavy metals, soil, rust, sediment, and other impurities, eliminating foul odor and taste.
Besides its anti-rust capabilities, the system has a natural look and a user-friendly design with no joints. As a result, your drinking water has never been safer in the Waterdrop King Tank filter.
In addition, the ultra-large-sized model of the filtration system will conveniently meet the water needs of households. You get all the accessories that is worth about $100 you need to fully use the Waterdrop King Tank gravity-fed water filter, helping you save more on accessory purchases.

Berkey Water Filter

Berkey is known for its efficient gravity-fed water filters, and this water filter system is not an exception. It delivers a great filtration performance thanks to in-depth research and an extensive developmental process. There are two black Berkey filter cartridges in this system. You can get up to 3,000 gallons of filtered water from each cartridge - or 6,000 gallons from both - before they are due for a replacement. This is the same capacity as the Waterdrop King Tank.
This product has been tested at Berkey’s independent lab, and the report is available online. The Berkey elements have been tested and found to be up to NSF standards. However, they are yet to be NSF certified, but the test report is enough conviction for customers looking to buy only an industry-backed product.

Should I Buy Waterdrop King Tank or Berkey Water Filter?

The ultimate decision between the two filter systems lies with you. That said, it can be a difficult choice to make. The Waterdrop King Tank and Big Berkey filter systems look the same and offer similar capabilities. However, you get more selection from the Berkey, while the King Tank gives you a premium filtration performance for less. The Waterdrop King Tank also comes with a free water level spigot to help you track your water level at a glance. The spigot is in addition to the stainless-steel stand and wrench, all of which are included in the package.
If you are looking for a unique user experience, you should opt for the King Tank - that is where Waterdrop excels.

What Are The Things to Consider When Choosing A Gravity Water Filter?

Because there are several gravity-fed water filters, it is best to consider several key factors when comparing them. Nevertheless, the most significant factors are filter quality and lifespan, tank capacity, and flow rate. This section discusses six things to consider when choosing gravity water filters, including;

Type Of Contaminants Removed

Most gravity water filters are capable of removing chlorine. However, some filters remove more than chlorine. These filters can remove fluoride, heavy metals, bacteria, and other chemicals, including pesticides and herbicides. Furthermore, some of these gravity filters soften water and replenish it with healthy minerals.

Filter Capability

The water quality a filtration system produces is one of the filter's essential features. Buying a water filter that cannot cope with water from wild resources is pointless. When investing in a water filter system, it is best to ensure that it generates healthy drinking water.

Filtration Performance

A significant factor when considering gravity-fed water filters is their filter element. The criterion for the filter element is the removal of bacteria, cysts, and protozoa to the barest minimum.
In most situations, drinking water is considered safe once there are no biological threats present. However, you will most likely need more than filtration of biological threats depending on where you live and your water conditions.

Flow Rate

Gravity-fed water filters do not have any pressure from the pipeline system pushing the water. Therefore, these gravity-fed water filters have a velocity slower than other water filter types. When filtering water with a gravity water filter, the system takes more time. Depending on the number of filters present in the filtration system, the water filter needs about 7 hours to filter between 4 and 7 gallons of water.


Although countertop filters are portable, they are not as portable as hanging filters. With hanging filters, taking them apart and slotting their components into one another is necessary for saving space. However, a substantial amount of room is essential for storing and carrying them.

Chamber Material

The food-grade 304 stainless steel is the most common chamber material for countertop water filters. The material prevents rust, keeping water fresh for long periods.
Generally, plastic and silicone are used in making hanging gravity water filters. When purchasing water filters, it is best to check if the material is food grade or BPA free from plastic. Fortunately, most hanging water filters fit this criterion.

What Are the Pros and Cons of Gravity-Fed Water Filters?


Gravity water filters do not require electricity for their filtration process. Also, you don't need to set up a connection to the water line or drill holes on your kitchen sink before operating the filter. You can also place the gravity water filter anywhere in your home, including tabletops or countertops.
Other benefits of the gravity water filter include its easy and seamless installation; you only need to set up the water filters components properly. Additionally, compared to buying bottled water, the gravity water filter is a more eco-friendly alternative. The gravity water filter is also available in several sizes, and because the filter lasts long, it requires less maintenance during use.


A significant disadvantage of the gravity water filter is the refilling; you have to refill the filter naturally whenever you need clean drinking water. Also, the parts of the filter can be pretty costly. The gravity filter takes longer to clean water, delaying your filtered water compared to other water filters. Therefore, it is advisable always to check how fast the gravity water filter unit can do its job before purchasing it.

Frequently Asked Questions

Are Gravity-Based Water Purifiers Effective?

Yes. The filtration process in gravity-based water filters is slow, ensuring that water has a longer contact time with the filtration media, making the process highly effective.

Is A Hanging Water Filter Better Than a Countertop Water Filter?

The two water filters are efficient, and none is better than the other. However, you may find out that one of the water filters suits your needs more. When considering a water filter, it is best to think about the usage – are you going to use the water filter at home or during trips? Countertop water filters are a better and more practical option for at-home use. Hanging water filters, on the other hand, are Kore suited for use during trips.

How Can You Use a Gravity Water Filter?

Using the gravity water filter is relatively straightforward. All you need do is fill the filter's top reservoir with water and let gravity do the rest. Like a pitcher water filter, the filtration system will push the water through the filters for cleaning into the lower storage tank. Afterward, you can fill your water bottle via the dispenser

When Should You Change Your Filters?

When the filtration process slows down, the system may take up to three or four times the regular time to filter water. At this point, the filters require a change. A change in water taste is also an indication that you need to change the filter

How Often Should You Clean the Filtration System?

Your countertop water filter requires a deep cleaning every two to three months. However, if your water deposits limescale in the holding tank due to its high mineral content, it is best to clean the water filter more regularly. On the other hand, hanging water filters require thorough washing and drying after using them on a trip. In cases where you are away from home for a long time, you can rinse out the filter during your travels.


Drinking water may not be clean due to the presence of contaminants that pose a health risk. Gravity Water filters are ideal for removing water contaminants by using the force of gravity. Furthermore, Gravity water filters do not require electricity for their operation or require high maintenance.
Get a gravity water filter today to enjoy clean, safe drinking water.