Filter guide for drinking water

filter guide

You’re considering getting a water filter but how do you find the right one? Do you ever needed a filter guide? Try with this drinking water filter guide.

The first question you should ask is what problem you want to solve?

  • Is your water drinkable but tastes and smells poorly?
  • Are you concerned about specific bacteria (Legionella, E.coli) or viruses (enteroviruses)?
  • Worried about trihalomethanes (THMs) forming in your water?
  • Is there a risk of lead contamination from your pipes?
  • Is the water too hard and you want to remove lime scale (calcium bicarbonate) from the water?
  • You simply want to ensure that your water is safe to drink?

See the water quality report guideline. Once you know what the problem you want to solve is then you can evaluate and choose the appropriate filter technology having as a reference our filter guide.

Secondly there are different types of installations in this water filter guide:

  • Water pitchers – just fill it up with water and it filters it for instant use or place in the fridge to keep cool. E.g. Soma and Brita
  • Faucet filters – installs directly on your faucet and usually have a switch to turn filtering on and off. E.g. Tapp Water, Culligan and PUR.
  • Counter top filters – connects to your faucet or standalone to be filled and filters the water for drinking. E.g. Berkey and Propur
  • Under the counter filtration – filters the water specifically for the kitchen with replacement cycles typically every 3 to 12 months. E.g. Culligan and 3M
  • Whole house water filtration system – filters all incoming water in house for kitchen faucets, appliances, bathroom and shower. E.g. PureEffects, 3M, GE, Aquasana
  • Shower filters – covered in a separate section on this website

Within each of these types there are different technologies used and here’s a summary table with how each one works.

Drinking water filter guide overview and what they remove:

Filter methodDescriptionRemoves
Caraffe in the fridgeTo simply get rid of the chlorine the simplest method is to leave a caraffe of unfiltered water in the fridge over night. Generally most of the chlorine evaporates in 12-24 hours.About 80-90% of the chlorine evaporates.
Grannular Active Carbon (GAC)Grannular activated carbon is made from raw organic materials (such as coconut shells or coal) that are high in carbon. Carbon is probably the most absorbent material known to man, and it is uniquely efficient because of thousands of tiny pores that can absorb. Some also use secondary media such as silver to prevent bacteria growth.Active charcoal carbon filters are most effective at removing chlorine, sediment, volatile organic compounds (VOCs), taste and odor from water. Remove most bacteria. They are not effective at removing minerals, salts, and dissolved inorganic compounds. Also reduces limescale and some metals such as lead.
Reverse Osmosis (RO)Commonly referred to as RO, is a process where you demineralize or deionize water by pushing it under pressure through a semi-permeable Reverse Osmosis Membrane. RO filters are usually combined with an active carbon filter to trap organic chemicals and chlorine or CTA (cellulose tri-acetate) membrane prior to the RO membrane.Capable* of removing 99%+ of the dissolved salts (ions), particles, colloids, organics, bacteria and pyrogens from the feed water (RO system should not be relied upon to remove 100% of bacteria and viruses).

* Capable = industrial grade RO systems

UV PurifierUV Water Purification systems use special lamps that emit UV light of a particular wavelength that have the ability, based on their length, to disrupt the DNA of micro-organisms. As water passes through a UV water treatment system, living organisms in water are exposed to UV light which attacks the genetic code of the microorganism and rearranges the DNA /RNA, eliminating the microorganism’s ability to function and reproduce.
Normally UV filters are combined with another fitler such as active carbon.
Remove 99.99 percent of bacteria and viruses that may be present in your tap water. See below for longer list.
OzoneA home based system is very similar to those used in municipalities except on a far smaller scale. They are systems that include a recirculation pump, an ozone generator, a water recycling tank, and an ozone line vent. Ozone drinking water purifiers are generally located at the water intake point for the home between the intake and the storage tank. Ozone also uses UV light but in this case to create unstable oxygen molecules.
Ozone is often combined with activated carbon filtration to achieve a more complete water treatment.
Ozone has been found to effectively remove 99 percent of all biological pathogens including Giardia and Cryptosporidium. It also is effective at removing iron and manganese as well as freeing up chlorine to kill even more microbes if used in a multiple step system.
Ion ExchangeThe ion exchange process percolates water through bead-like spherical resin materials (ion-exchange resins). Ions in the water are exchanged for other ions fixed to the beads. The two most common ion-exchange methods are softening and deionization. Deionization is generally used in combination with active carbon filters. Softening is primarily used before RO filters.Primary use is to soften the water and to reduce contaminets. Generally used in combination with a active carbon or a RO filter. Also frequently marketed as making the water alkaline (pH level above 7) and thus healthier for the body.
DistillationWater is first heated to boiling. Then the water vapor rises to a condenser where cooling water lowers the temperature so the vapor is condensed, collected and stored. Most contaminants stay behind in the liquid phase vessel.Removes most contaiminats. Destillation is mostly used in industrial processes.
BoilingNot really a filter system but as it’s used by many people as a last resort it’s included.Removes bacteria and viruses


Pros and cons of each of the filter technologies? Keep reading our filter guide:

Filter methodProsCons
Grannular Active Carbon (GAC)Easy to install and replace filters (with the faucet and carafe models)

Effective for the most common water issues in developed countries

Minimum waste of water

Leaves minerals and salt in the water

Cost as little as €60 per year (e.g. Tapp Water)

Doesn’t filter out all contaminants such as bacteria and viruses.

The best filters remove 90% or more of the chlorine but may still leave some poor taste.

Doesn’t reduce the hardness of water*

Home filters don’t work at high temperatures or with high pressure and therefore not appropriate for shower filters.

* Note: Some filters like TAPP 1 reduces Calcium which results in the perception of softer water

Reverse Osmosis (RO)Output is very clean water and can be used to make undrinkable water potable (drinkable)

Filter replacement approximately every 2-12 months (differs by brand and utilization)

Waste as much as 6x the water output

Remove many of the desirable minerals from the water

RO has a hard time removing or reducing calcium and magnesium – the minerals that make water hard so may require water softening before

Expensive and difficult to install and maintain versus caraffe and faucet filters (requires a professional)

UV PurifierVery effective in removing bacteria and viruses
Reliable and cost effiecient  – only lamp & sleeve replaced annuallyClean – no dirty parts to dispose of
Cannot be used on it’s own in most cases

Does not remove any other contaminants from water such as heavy metals, salts, chlorine or man-made substances like petroleum products or pharmaceuticals.

UV light is only able to work if water is clear. If the water is murky or contains “floaties,” a pre-filter should be used; UV light cannot effectively reach microorganisms because the rays are blocked by the other particles.

OzonePrimarily a disinfectant that effectively kills biological contaminants.

Oxidizes and precipitates iron, sulfur, and manganese so they can be filtered out.

Will oxidize and break down many organic chemicals including many that cause odor and taste problems.

More expensive than the other technologies

Unstable oxygen (i.e., ozone) acts as an oxidant in the body and may contribute to cellular damage, aging, diseases, etc.

Ion ExchangeRemoval of >98% contaminants

No wasted water

No electricity needed

Fast flow rate

Ideal for whole house filters

Does not effectively remove particles, pyrogens or bacteria

High operating cost over time

There is no scientific proof that alkaline water is better for the health

DestillationRemoves a broad range of contaminants


Does not remove bad taste/odor

Consumes large amounts of energy

System usually takes a large space on counter

Does not contain any minerals or salt afterwards

May not remove pesticides and herbicides

BoilingDoesn’t require any equipment

Vastly reduces risk of getting ill from short term consumption of water

Does not remove a lot of contaminents like metals

Very expensive and time consuming method for high volumes of water

So which filter should you choose? Faucet filter, sink water filter, Destillation … Choose between the bests options for you!

In most cases it’s sufficient with an active carbon filter to remove odor, bad taste and contaiments but if your water report indicates specific issues with your water or if you have other concerns such as pH level, calcium or fluoride then pick the filter that fits best with your needs. Take a close look to our filter guide and you will be able to decide wisely.

Offers / discounts:

Use promo / coupon code “todosobreelagua” for 10% discount on the products on TAPP Water.


WHO, EPA, EU, Water Institute of Barcelona, Water institute of Granada, Water University in Stockholm, Water Benefits & Health and more.