Is there a filter that removes everything?

No. Each technology has a limited scope. Reverse osmosis is the broadest, but it also removes useful minerals and rejects water; a pitcher mainly acts on taste. The choice always starts from an identified problem, not from a global promise.

Is reverse osmosis necessary for everyone?

No. It is mainly justified when a problematic parameter is documented, such as high nitrates. For compliant water where only the chlorine taste is bothersome, it is a disproportionate answer in both cost and maintenance.

Should osmosis water be remineralised?

Osmosis also removes calcium and magnesium, which contribute to mineral intake and to taste. That is why a remineralisation cartridge is often useful, especially if tap water had been a source of minerals in your diet.

Is a filter pitcher enough?

It is enough if your goal is taste comfort on water that is already compliant. It is not enough if the problem involves nitrates or lead: in those cases you need a suitable technology, or even work on the pipes.

Does a softener filter drinking water?

No. A softener acts on hardness, not on drinkability: it removes neither nitrates, nor pesticides, nor lead, and it increases sodium content. That is why an unsoftened tap is often kept for drinking and cooking.

Decision guide

Pitcher, faucet filter or reverse osmosis: which water filter should you choose?

There is no universal filter. The right device depends first on your water's actual problem: a chlorine taste, excess limescale, nitrates or lead do not call for the same technologies.

So the first step is not a purchase, but an assessment. The official analyses for your municipality show what your tap water really contains, and the diagnostic helps you turn those results into concrete priorities.

And if the water is compliant and you like its taste, the honest answer is simple: no filter is needed. Filtering water that is already good adds cost and maintenance with no demonstrated benefit.

Run the diagnostic for my water See my municipality's water quality

This page recommends no brand and contains no commercial links. Cost ranges are indicative and vary widely with the model, the installation and household consumption.

Decision table: which solution for which problem?

Find your problem in the first column, then read across the row: it is the fastest way to rule out solutions that do not fit your situation.

Suitability of the main domestic treatment solutions depending on the problem encountered.
Problem	Activated carbon pitcher	Faucet filter	Reverse osmosis	Water softener	Specific ion exchange resin
Chlorine taste, odour	Suitable	Suitable	Suitable	Not suitable	Not suitable
Limescale, hardness	Not suitable	Not suitable	Partial	Suitable	Partial
Nitrates	Not suitable	Not suitable	Suitable	Not suitable	Suitable
Lead	Not suitable	Partial	Suitable	Not suitable	Not suitable
Water already compliant and pleasant to drink	Not suitable	Not suitable	Not suitable	Not suitable	Not suitable

Key point: pitchers and activated carbon filters address taste, not nitrates or lead. For nitrates, only reverse osmosis or a specific ion exchange resin are relevant. For lead, a certified filter (NSF/ANSI 53 type standard) is an interim measure: the lasting fix remains replacing the pipes involved.

Nitrates in water Lead in water Hard water: what to do?

Each solution in detail

What each technology actually treats, the maintenance it requires, its limits and its rough cost range.

1.Activated carbon filter pitcher

Mainly addresses chlorine taste and odour, and retains part of some metals. Maintenance: regular cartridge replacement and frequent cleaning of the pitcher, otherwise it becomes a favourable environment for bacteria. Limits: no reliable effect on nitrates, slow flow, limited capacity. Cost: low purchase price plus a recurring cartridge budget, typically a few tens of euros per year.

2.Faucet filter

Same principle as the pitcher, but in continuous flow: more practical day to day and with no container to handle. Maintenance: cartridge replacement based on filtered volume. Limits: essentially acts on taste, odour and some particles, not on nitrates; check compatibility with your tap. Cost: moderate purchase, consumables comparable to a pitcher.

3.Reverse osmosis

An under sink system that retains a very large share of dissolved substances, including nitrates. It is the most complete solution, but with real trade-offs: water rejected to the drain while running, space taken under the sink, prefilter and membrane replacement, and removal of useful minerals, which often makes remineralisation desirable. Cost: several hundred euros to install, plus yearly maintenance.

4.Water softener

This is not a drinking water filter: it exchanges calcium and magnesium for sodium to reduce hardness. It protects appliances and improves comfort, but it raises sodium content and removes valuable minerals. Many installations therefore keep an unsoftened tap for drinking. Maintenance: salt, settings and periodic disinfection. Cost: high investment, plus salt and servicing.

5.Specific ion exchange resin

A selective resin designed to target one precise parameter, for example nitrates. A relevant solution when the problem is identified and documented by analyses. Maintenance: resin regeneration or replacement, with monitoring essential to avoid release back into the water. Limits: treats only one parameter at a time. Cost: intermediate and highly variable depending on the device.

None of these systems replaces official health monitoring. If a non compliance is confirmed, the health authority and your water utility indicate what to do.

Filter pitcher comparison Bottled water or filtration: the real cost Chlorine taste: simple solutions

How to decide in 3 steps

1. Know your water

Start with facts: check your municipality's analyses and run the diagnostic to situate your water. Without that starting point, any purchase is guesswork.

2. Identify the problem

Name the nuisance precisely: chlorine taste, limescale deposits, high nitrates, older pipes suspected of containing lead. Each problem has its dedicated page on InfoEau.