Water is an essential part of our daily lives. We use it to cook meals, prepare tea or coffee, and stay hydrated throughout the day. The quality of the water we drink directly affects on our overall health. For many households, that means thinking beyond tap water, which may still contain small amounts of contaminants.
Filtered water is often a better choice, but there are many types of water filter systems on the market, from simple jugs to multi-stage purifiers, and each one has its own advantages and disadvantages. Making an informed decision means matching the system’s capacity to filter your local water quality, budget, and usage.
In this article, we explain the main types of water filters available for home use.
What are water filters?
Water filters are devices that treat water by reducing unwanted substances, so it is safer and more pleasant to drink. They use different technologies, but all work by passing water through materials or membranes that trap particles, adsorb chemicals or inactivate microorganisms.
Why water filtration matters
Common contaminants often include microorganisms (such as bacteria and some parasites), heavy metals like lead and copper, chlorine and its by-products, as well as pesticides and industrial chemicals. Many systems also deal with visible particles such as rust, sand and silt, and some modern filters help lower levels of newer concerning substances like PFAS and other emerging pollutants.
Water quality is closely linked to health, safety and the environment. Reducing harmful contaminants can limit long-term exposure, which is especially important for children, pregnant women and older adults. For example, long-term exposure to lead in drinking water has been linked to developmental problems in children and cardiovascular issues in adults, while certain PFAS have been associated with effects such as changes in cholesterol levels and immune responses.
Better-tasting filtered water also encourages regular hydration and can help households cut back on bottled water and plastic waste.
What are the four different types of water filters?
The four main types of water filters used in homes are reverse osmosis systems, UV light sterilisers, activated carbon filters, and sediment filters.
These four technologies form the basis of most modern water filter types, and many home systems combine two or more of them. In the next sections, we look at each one in more detail.
1. Reverse osmosis
Reverse osmosis systems use pressure and a semi-permeable membrane to separate water from many dissolved substances. In a typical unit, water first passes through pre-filters to remove larger particles and chlorine, then is pushed across the membrane. Most contaminants stay in a concentrated stream that is sent to waste, while the purified water (permeate) is collected for drinking. In practice, reverse osmosis filters almost always form part of a multi-stage system.
The benefits and limitations of reverse osmosis
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Benefits |
Limitations |
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RO has a wide treatment range and can reduce many heavy metals, salts, certain pesticides, medicine residues and some PFAS. |
RO produces a residual stream that carries away concentrated contaminants as part of the filtration process. |
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Carbon stages help improve taste and odour alongside contaminant reduction. |
Produces ‘residual water,’ which is about 1 litre for every 3 litres of filtered water. This can be reused for non-drinking purposes such as watering plants or cleaning. |
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Routine care is straightforward, with descaling as needed and filter changes typically every 6 months, 1 year or 2 years, depending on the filter, usage and water quality. |
The system requires regular upkeep to maintain performance, including timely filter replacement and occasional descaling, especially in hard-water areas. |
AquaTru’s patented 4-stage process combines mechanical pre-filtration, carbon stages and a high-performance membrane, and is independently tested and certified by IAPMO to NSF/ANSI Standards 42, 53, 58 and 401 for the reduction of 83 contaminants, including many industrial pollutants and PFAS.
2. UV light sterilisers
UV light sterilisers use ultraviolet light to inactivate microorganisms in water, such as bacteria, viruses and some protozoa. Inside the unit, water flows past a lamp that emits UV-C light at a specific wavelength. This light damages the DNA or RNA of the microorganisms so they can no longer reproduce, effectively neutralising them and reducing the risk of infection.
The benefits and limitations of UV light sterilisers
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Benefits |
Limitations |
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UV light sterilisers use ultraviolet light to inactivate microorganisms in water, such as bacteria, viruses and some protozoa. |
UV systems do not remove dissolved contaminants from water. |
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UV-C light damages the DNA or RNA of microorganisms so they can no longer reproduce, which helps reduce infection risk. |
UV does not filter out particles like rust or sand. |
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UV treatment is chemical-free and does not add anything to the water, so taste and odour remain unchanged. |
High turbidity can reduce UV effectiveness because particles can shield microorganisms from the light. |
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UV works quickly as water passes the lamp and is generally energy-efficient. |
UV is usually paired with pre-filtration for particles and often carbon or other stages for chemicals. |
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For well water or as an extra barrier against microbes, a correctly sized and maintained unit can be a very effective addition. |
UV provides strong microbiological protection, but it is not a complete solution on its own for overall drinking water quality. |
3. Activated carbon filters
Activated carbon filters use highly porous carbon to attract and hold certain contaminants as water passes through. The carbon has a very large internal surface area, so molecules such as chlorine, many taste- and odour-causing compounds, some pesticides and volatile organic compounds (VOCs) can adsorb onto its surface. Depending on the design, this carbon may be in block form or as granular activated carbon in a cartridge.
The benefits and limitations of activated carbon filters
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Benefits |
Limitations |
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Activated carbon filters use highly porous carbon to attract and hold certain contaminants as water passes through. |
Standard activated carbon on its own is much less effective at reducing many harmful substances. |
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The carbon’s large internal surface area helps adsorb molecules such as chlorine, many taste- and odour-causing compounds, some pesticides and VOCs. |
Activated carbon does not reliably remove microorganisms such as bacteria and viruses. |
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The main benefit is a noticeable improvement in taste and smell, which can make tap water more pleasant to drink. |
Performance drops as the carbon becomes saturated, so the cartridge needs replacing on schedule. |
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It does not require electricity and filter changes are usually straightforward, which suits everyday home use. |
Best combined with mechanical filtration and a reverse osmosis membrane for more complete treatment. |
4. Sediment filtration systems
Sediment filtration systems are designed to remove physical particles from water, such as dirt, sand, rust and other visible or microscopic debris. They use cartridges made from materials like pleated fabric, string-wound fibres or spun polypropylene, with a specific pore size. As water flows through, particles larger than that pore size are trapped in the filter, while the water passes on to the next stage.
The benefits and limitations of sediment filtration systems
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Benefits |
Limitations |
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Sediment filtration systems remove physical particles from water, such as dirt, sand and rust. |
Sediment filtration only targets particulate matter and does not address dissolved substances. |
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Cartridges use a set pore size, so particles larger than that pore size are trapped as water flows through. |
It does not reduce chlorine, PFAS, or other contaminants that remain dissolved in the water. |
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Sediment filters improve clarity and help water look and feel cleaner. |
It does not inactivate microorganisms such as bacteria or viruses. |
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By catching grit and rust, they can help prevent deposits in kettles, taps and appliances. |
If used on its own, it will not meaningfully change taste or odour caused by chemicals. It is also most effective as a first stage, rather than a standalone solution for drinking water quality. |
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Maintenance is usually straightforward, with cartridges replaced or cleaned based on water quality and usage. |
Filters can clog faster in high-sediment areas, so replacement intervals may be shorter in those homes. |
One extra type: ion exchange filters
Ion exchange filters work by swapping certain dissolved ions in the water for others held on a resin. The classic example is a water softener, where hardness minerals such as calcium and magnesium are exchanged for sodium (or sometimes potassium). As hard water passes through the resin bed, calcium and magnesium bind to the resin and sodium ions are released into the water in their place.
The benefits and limitations of ion exchange filters
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Benefits |
Limitations |
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Ion exchange filters swap certain dissolved ions in the water for others held on a resin. |
They mainly change the mineral balance, rather than addressing every type of water quality issue. |
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In water softeners, calcium and magnesium are exchanged for sodium or sometimes potassium. |
Most other substances remain unchanged, including microorganisms, many organic chemicals, and pesticides. |
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The main benefit is softer water, which helps limit scale build-up in kettles, boilers, pipes and appliances. |
Units need regular regeneration with salt to restore the resin’s capacity. |
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Specialised resins can be designed to target particular ions, such as nitrate or some heavy metals, where those are known issues. |
In most homes, ion exchange works best alongside broader treatment such as carbon or reverse osmosis, rather than as a stand-alone drinking water solution. |
What is the best filter type for drinking water?
The best filter type for drinking water depends on several factors, including the quality of your local supply, how many people are there in your household, and how much space and budget you have for a system. Checking recent water reports or known issues in your area is a useful first step before choosing between different types of water filters.
Each technology has a role. UV systems are strong where microorganisms are the main concern, activated carbon works well for taste, odour and certain chemicals, sediment filters protect against particles, and ion exchange is helpful in hard-water areas where limescale is the priority.
For overall drinking water quality at home, reverse osmosis offers the greatest benefits. An RO system, complete with pre-filters, a membrane and a final polishing stage, can reduce up to 99% of all harmful substances in your water as well as provide better taste.
7 popular types of water filtration systems: pros and cons
Beyond the core technologies, there are several types of water filtration systems to choose from, including countertop and under-sink units, whole-house systems, jugs, bottles, gravity filters and electric dispensers. Below, we outline the main pros and cons of each to help you compare cost, convenience, upkeep and filtration level for a typical home.
1. Countertop water filter
- Pros: Countertop water filters like AquaTru Classic and Carafe are plug-and-play, require no plumbing and are easy to move if you change your kitchen layout or home.
- Cons: They suit most kitchens, although very small worktops may feel a bit crowded, and you do need to refill the tank regularly.
2. Under sink water filter
- Pros: Under sink water filters are installed in the cupboard below your sink and connect directly to a dedicated tap or your existing mixer, so purified water is always on hand without occupying worktop space. They are discreet and ideal for everyday cooking and drinking.
- Cons: They do require professional installation and use some storage space under the sink.
3. Whole house water filter
- Pros: A whole house water filter sits on your main incoming water line so that every tap, shower and appliance receives treated water. It can improve overall water quality, reduce sediment and help protect plumbing and equipment.
- Cons: The trade-offs are higher upfront cost, professional installation and regular maintenance, and many homes still use a separate drinking-water filter at the sink because the whole house filter does not remove all the contaminants from the water.
4. Pitcher filter
- Pros: Pitcher filters use a small, activated carbon cartridge in a jug that helps reduce chlorine and improve taste and odour. They are low-cost, easy to use and portable, making them a simple starting point for basic filtration.
- Cons: The downsides are limited capacity, slower gravity flow, frequent filter changes (and waste) and only modest contaminant reduction compared with multi-stage systems such as reverse osmosis.
5. Bottle filter
- Pros: Bottle filters are reusable bottles with a small built-in cartridge, often using activated carbon to improve taste and reduce chlorine as you drink. They are lightweight, portable and handy for travel or commuting.
- Cons: They have limited filter capacity, need frequent refilling and regular cartridge changes, and only offer basic filtration.
6. Gravity filter
- Pros: Gravity filters use an upper chamber and a cartridge so water slowly passes through to a lower container under gravity alone. They are simple to use, need no electricity and can work where infrastructure is limited.
- Cons: Filtration is slow, units need regular cleaning, and they mainly handle relatively minor water issues.
7. Electric filter
- Pros: Electric water filters are plug-in units that use a powered pump to move water through internal cartridges, giving faster, automatic filtration than gravity-based systems. They can be convenient for busy households.
- Cons: They depend on electricity, are often more expensive, need regular replacement filters and their ability to deal with harmful substances can vary.
AquaTru: a powerful type of water purifier for clean water
AquaTru is designed for families who want reliably clean drinking water without complicated installation. All models are built around AquaTru’s patented 4-stage reverse osmosis technology, combining mechanical pre-filtration, carbon stages and a high-performance membrane. Together, these stages reduce a wide range of dissolved substances while also improving taste and smell.
There is a model for almost every kitchen. The Classic and Carafe countertop units are plug-and-play, sit neatly on the worktop and can be moved if you change home or layout. The Under Sink system fits discreetly in the cupboard and automatically refills a generous tank, giving you a steady supply of purified water on demand. Long-lasting filters, with change intervals measured in months or years, help keep maintenance predictable and reduce plastic waste compared with bottled water.
Taste is a factor in how much water people drink at home. People who like the taste of their tap water tend to drink more than those who do not.
Check AquaTru today and choose the right purifier that best fits your home setup, needs, and lifestyle.
