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Water Purification

Water purification is a crucial process aimed at enhancing the quality of water by eliminating undesired chemical compounds, organic and inorganic materials, as well as various biological contaminants. This procedure ensures that water is safe for consumption, preventing various waterborne diseases and maintaining the health of individuals and communities. The process incorporates various methods, such as distillation, where liquid is converted into vapor and then condensed back into liquid form, and deionization, which entails the removal of dissolved salts through ion extraction.

Although water purification serves an essential purpose, it is important to recognize that the water quality standards may vary across different regions, often dictated by government regulations or international guidelines. This means that the specific contaminants targeted and the purification methods employed can differ based on local requirements and the specific water sources being utilized.

When it comes to residential water purification, there are a range of options available for homeowners, from filtration systems that can be installed in the entire house to portable water filter pitchers. These options give households the ability to select the most suitable solution for their needs, ensuring access to clean and safe drinking water for all family members.

Water Purification

Water Purification Basics

Contaminants and Pathogens

Water purification is an essential process to ensure the safety and quality of drinking water. Contaminants that can be found in water include:

  • Chemical compounds (inorganic and organic materials)
  • Heavy metals
  • Dissolved minerals
  • Bacteria
  • Viruses
  • Protozoa

Impurities in water can affect its taste and can cause health issues if not properly treated. The primary goal of water purification is to create clean, safe drinking water free from these contaminants and pathogens.

Methods and Technologies

There are various methods and technologies used for water purification, such as:

  1. Chemical Treatment: This method involves the addition of chemicals, like chlorine or chloramine, to the water to kill bacteria, viruses, and other microorganisms.
  2. Filtration: Filtration systems remove particles from water by passing it through a filter media. The most common types of filters are:
    • Activated carbon filters
    • Sediment filters
    • Ceramic filters
  3. Distillation: This process converts water into vapor and then condenses it back into liquid form, effectively removing dissolved salts and other impurities.
  4. Deionization: Ion exchange technology is used to remove dissolved salts and other ions from water.
  5. Ultraviolet (UV) Purification: This method uses UV light to kill microorganisms like bacteria, viruses, and protozoa, making it an ideal option for households using surface water or well water sources.

Regular maintenance of purification systems is necessary to ensure their efficiency and the quality of the treated water. The costs involved in these systems may vary, with UV filters averaging $600-$1,200 upfront and $100-$150 per year for maintenance.

By using these methods and technologies, it is possible to achieve clean and safe drinking water, improving overall taste and minimizing health risks from contaminants and pathogens.

Types of Water Filters

Water Filter Pitchers

Water filter pitchers are a convenient and accessible option for filtering tap water at home. Popular brands like Brita and Pur offer pitchers with built-in filters that remove contaminants such as chlorine, copper, and lead. These pitchers typically use activated carbon or carbon block filters, which help to improve the taste and odor of the water. To use, simply fill the pitcher with tap water and allow it to pass through the filter before pouring it into a glass.

Water Bottle Filters

Water bottle filters are portable and practical for on-the-go filtration needs. Brands such as Aquasana and Brita offer water bottles equipped with built-in filters, which help to remove contaminants and improve overall water quality. These bottle filters usually incorporate activated carbon filters and may also include features like UV sterilization. To use, simply fill the bottle with tap water and drink through the built-in filter straw or spout.

Shower Water Filters

Shower water filters reduce the exposure to impurities and contaminants commonly found in tap water while showering. Popular brands like Aquasana and Soma offer shower filters that use various filtration methods, such as:

  • Carbon block filters: for reducing chemicals like chlorine
  • Ceramic filters: for blocking sediment and bacteria
  • KDF (Kinetic Degradation Fluxion) media: for removing heavy metals and controlling bacteria growth

To install, attach the shower filter between the showerhead and the water pipe. These filters work to reduce impurities like chlorine, which can benefit both hair and skin health by preventing dryness and irritation.

Sediment Filters

Sediment filters are specifically designed to remove particulate matter, such as sand, silt, and rust, from water sources. They are commonly used in residential and commercial water treatment systems as a pre-filter to protect other filters or devices from clogging or damage. Sediment filters are made with various pore sizes and materials, such as:

  • Spun polypropylene: for filtering out rust and sediment particles
  • Pleated polyester: for increased surface area and filtering capacity
  • Melt-blown polypropylene: for tight micron rating control

To install, connect the sediment filter to the water line before your main water treatment device or directly to a faucet for point-of-use filtration. Regularly inspect and replace the filter cartridge as needed to maintain optimal filtration performance.

Filtration Media

Activated Carbon

Activated carbon, also known as activated charcoal, is a commonly used filtration media in water purification systems. It is typically composed of carbonaceous materials with high surface area, allowing it to capture and hold contaminants effectively. Activated carbon can remove various impurities, such as chlorine, volatile organic compounds (VOCs), and unpleasant tastes and odors from water. There are two main types of activated carbon filters: granular activated carbon (GAC) and carbon block.

  • Granular Activated Carbon (GAC): Contains loose particles of activated carbon, which water flows through for contamination removal.
  • Carbon Block Filters: Compressed blocks of activated carbon offering better contaminant removal and flow rates than GAC filters due to their denser structure.

Ceramic Filters

Ceramic filters utilize porous ceramic material to filter out contaminants from water. They provide effective filtration for sediment, bacteria, and protozoa, making them suitable for treating drinking water. Ceramic filters can be cleaned and reused multiple times, which helps reduce costs and waste. There are two types of ceramic filters:

  • Ceramic Candle Filters: These are shaped like a cylinder or a cone and have a hollow core, allowing water to flow through the porous ceramic material.
  • Ceramic Disc Filters: These filters consist of multiple ceramic discs stacked together, also providing effective filtration and a larger surface area for water to pass through.

Sand Filters

Sand filters are a traditional and simple filtration method that uses layers of sand to remove sediment, turbidity, and some pathogenic microorganisms from water. Water passes through the layers of sand, and particles are trapped within the sand grains, clarifying the water. Sand filters can be used for various applications, such as pool filtration, drinking water treatment, and wastewater treatment. There are several types of sand filters:

  • Slow Sand Filters: Water slowly passes through a bed of fine sand, removing contaminants through both physical and biological processes.
  • Rapid Sand Filters: These filters use coarser sand and operate at higher flow rates compared to slow sand filters, often used in large-scale water treatment systems.

Cloth Filters

Cloth filters employ fabric material, usually made of synthetic fibers like polyester or polypropylene, to trap contaminants in water. They are typically used for liquid filtration in industrial processes, food and beverage manufacturing, and wastewater treatment. Cloth filters are cost-effective and can be replaced or cleaned as needed. There are various types of cloth filters:

  • Bag Filters: Water passes through a fabric bag, which captures particulates and contaminants.
  • Filter Press: Cloth filters are used in combination with filter plates, forming a chamber that captures solid particles while allowing liquid to pass through.

Removal of Specific Contaminants

Heavy Metals

Heavy metals, such as lead, arsenic, mercury, copper, zinc, and cadmium, can be harmful to human health when present in water. To remove these contaminants, various techniques can be employed, including:

  • Precipitation: Compounds are added to the water to react with the heavy metals, forming insoluble substances that can be easily removed using sedimentation or filtration.
  • Ion exchange: This process involves passing water through a resin that selectively binds to heavy metals, effectively removing them from the water.
  • Reverse osmosis: This pressure-driven filtration method utilizes a semi-permeable membrane to remove the heavy metals from water.

Chemical Contaminants

Common chemical contaminants such as pesticides, fluoride, chlorine, and chlorine dioxide can be effectively removed using the following methods:

  • Activated carbon filters: These filters utilize a process called adsorption to remove chemicals from water. Contaminants adhere to the surfaces of activated carbon granules, effectively reducing concentrations in the water.
  • Air stripping (Packed Tower Aeration or PTA): This process is useful for removing volatile organic compounds (VOCs) and other taste- and odor-producing compounds by encouraging them to evaporate from the water.
  • Advanced oxidation processes (AOPs): AOPs utilize strong oxidizing agents to break down complex organic contaminants into simpler, less harmful forms.

Biological Contaminants

Pathogens, such as bacteria, viruses, and protozoa, can be eliminated from water using the following methods:

  • Chlorination: Adding chlorine to water is a common disinfection method that can effectively kill most types of pathogens.
  • Ultraviolet (UV) disinfection: UV light can inactivate pathogens by damaging their genetic material, rendering them unable to reproduce.
  • Boiling: Bringing water to a rolling boil for at least one minute can ensure the complete inactivation of most biological contaminants.

By employing a combination of these techniques, water can be purified effectively, removing specific contaminants and ensuring safe drinking water.

Purification Methods for Outdoor and Emergency Situations

Boiling Water

One of the most effective water purification methods is boiling water. This is an ideal approach for outdoor and emergency situations, such as camping or during a natural disaster. To ensure the water is safe to drink, simply fill a pot with water and bring it to a rolling boil for at least one minute. Boiling effectively eliminates most pathogens, bacteria, and other contaminants. Once the water has cooled down, it is safe to consume.

Water Purification Tablets and Drops

Water purification tablets and drops are another reliable option for purifying water in outdoor and emergency scenarios. Most of these products contain iodine or chlorine-based compounds that help to kill bacteria, viruses, and parasites. When using purification tablets or drops, follow the instructions on the packaging for the correct dosage and waiting time:

  • For Clear or Warm Water: Use 5 drops of iodine-based solution or the recommended amount of chlorine tablets per quart of water.
  • For Cold or Cloudy Water: Use up to 10 drops of iodine-based solution or the recommended amount of chlorine tablets per quart of water. If the water is cloudy, it is advisable to filter it through a clean cloth, paper towel, or coffee filter before adding the purification agent.

Portable Water Filters

Portable water filters are an efficient solution for both outdoor enthusiasts and emergency situations. They are an excellent choice for purifying tap water or natural water sources, like rivers and streams. These filters come in a variety of forms, including:

  • Filter Bottles: Designed for individual use, these bottles have built-in filters that remove contaminants as you drink from them. The Lifestraw Filter Bottle is a popular example.
  • Gravity Filters: Suitable for groups, these filters use gravity to draw water through a filter element, providing clean water for multiple users. A well-known option is the Life Straw Gravity Filter.

It is important to follow the manufacturer’s guidelines for proper use and maintenance of portable water filters. These devices can effectively remove various contaminants, including bacteria, protozoa, and particulate matter in most cases. However, they may not always remove viruses or chemical contaminants, so additional purification methods, such as boiling or using purification tablets, may be necessary.

Maintenance and Replacement of Filters

Replacement Schedules

Regular maintenance and replacement of water filters are crucial for preserving the efficiency and effectiveness of your water purification system. The frequency of filter replacement depends on the type and brand of the purification system, as well as the quality of the water being filtered. Here are some general guidelines for three common types of filters:

  • Sediment Filters: Replace every 3-6 months
  • Activated Carbon Filters: Replace every 6-12 months
  • Reverse Osmosis (RO) Membranes: Replace every 2-3 years

Remember that these are general guidelines, and it’s crucial to follow the recommendations provided by your system’s manufacturer.

How to Properly Replace Filters

Following the proper steps for replacing filters ensures the longevity and effectiveness of your water purification system. Below is a general procedure for replacing filters, but always consult your system’s manual for specific instructions.

  1. Turn off the water supply to the filtration system.
  2. Release pressure from the system by opening the faucet or vent valve.
  3. Remove filter housing or sump, and place it on a waterproof surface.
  4. Carefully remove the old filter cartridge.
  5. Dispose of the old filter according to your local regulations or recycling guidelines.
  6. Clean the filter housing with warm soapy water, then rinse and dry thoroughly.
  7. Insert the new filter cartridge into the housing, ensuring that it is properly seated.
  8. Reattach the housing or sump to the system, and tighten it securely.
  9. Turn the water supply back on, and check for leaks.
  10. Flush the system according to the manufacturer’s instructions before using the filtered water.

By adhering to proper maintenance and filter replacement schedules, you can enjoy the benefits of clean, healthy water for years to come. However, it’s essential to consult your system’s manual for specific information about your water purification system to ensure its performance and longevity.

Factors to Consider When Choosing a Water Purification System

When choosing a water purification system, it is important to consider several factors such as effectiveness, cost, and ease of use. Below, we discuss each of these factors to help guide you in making an informed decision.


Effectiveness is a crucial aspect to consider when selecting a water purification system. The type of purification system you choose should effectively remove contaminants, such as:

  • Suspended particles
  • Parasites
  • Bacteria
  • Algae
  • Viruses
  • Fungi

It is essential to identify the specific contaminants present in your water and the system’s effectiveness in removing them. Keep in mind that no filtration system is 100% effective in removing all contaminants, so it is necessary to know which contaminants are most important to be eliminated based on your intended use.


Cost plays an important role when choosing a water purification system. It is vital to consider both the upfront cost of the system and the ongoing costs for filter replacements or maintenance. When comparing systems, remember to weigh the costs against the potential savings, such as reduced spending on bottled water, detergents, and appliance maintenance.

Ease of Use

The ease of use and installation of a water purification system is another key factor to consider. There are various types of systems available, which include:

  • Water filter pitchers
  • Faucet-mounted filters
  • Built-in faucet filters
  • On-counter filters
  • Under-sink filters
  • Whole-house treatment units

Some systems, like water filter pitchers and faucet-mounted filters, are more straightforward to install and use, while others, like under-sink filters and whole-house treatment units, may require professional installation. The choice of system should depend on your preferences, the amount of space available, and your level of expertise in handling installations and maintenance tasks.

In conclusion, when selecting a water purification system, take the time to consider the factors of effectiveness, cost, and ease of use in order to make the best decision for your needs.