What is worth knowing about your water? Eight questions people ask most often.
Clear water is not automatically problem-free, and no filter is universal. On this page you will find honest answers — without scare tactics and without marketing promises — and what you can actually do about each one.
No scare tactics. We untangle the context.
Water quality cannot be judged by appearance, taste, or filter brand. A sensible proposal starts with one question: what needs to be removed, why, and under what operating conditions?
Where water comes from
Surface water, wells, mains, and recycled water each carry different risks.
What needs to go
Taste, odour, micropollutants, and microorganisms each require different treatment.
How water moves
Flow rate, temperature, and contact time affect what a filter can actually capture.
Verify the outcome
Measure before and after intervention — never accept a catalogue specification alone.
Short answer immediately. Detail only if you want it.
For each point you will find how things actually are and what you can do about it. The technical explanation is in the collapsible layer — open it if you want to know more.
Myth 01 If water is clear and odourless, it is fine.
In reality
Most substances that matter are invisible and odourless. Pesticides, pharmaceuticals, nitrates, or elevated microbial counts cannot be detected by eye or nose.
Appearance tells you nothing about what is dissolved in the water.
More detail
Public water supply is regulated and undergoes routine monitoring. Private water sources (wells, boreholes) are the responsibility of the property owner and are frequently not tested at all.
Modern contaminants — pesticide residues, pharmaceutical traces, disinfection by-products — occur at trace concentrations. They are not perceptible to the senses, but some are biologically active even at very low levels.
Clear appearance is the result of treatment or natural clarity of the source — not a sign that all dissolved substances have been removed.
Myth 02 Chlorine in water is just a matter of taste.
In reality
Chlorine is a powerful oxidising disinfectant. Its purpose is to control microorganisms — but its chemical activity does not stop there.
As chlorine travels through water, it can react with natural organic matter, nitrogen-containing compounds, bromides, iodides and other substances. These reactions create disinfection by-products (DBPs).
More than 700 different DBPs have been described in scientific literature, while routine drinking-water monitoring covers only part of this chemical spectrum.
The issue is therefore not simply whether you can smell chlorine. The more important question is: what has chlorine reacted with — and what is left in the water when it reaches the tap?
More detail
Residual free chlorine may still be present when water reaches the consumer. It can affect taste and odour, but reducing the issue to taste alone misses the more important chemistry taking place during treatment and distribution.
Chlorine can generate several groups of reaction products, including trihalomethanes (THMs), haloacetic acids (HAAs), chloramines, halogenated acetonitriles, halogenated furanones, aromatic and alicyclic DBPs, and other organic and inorganic reaction products.
Some of these substances are regulated. Many others are not routinely measured. Meeting a legal limit does not mean the substance is absent; it means that the measured concentration of a regulated parameter complies with the applicable requirement.
Research has identified DBPs with mutagenic, genotoxic, cytotoxic and, in defined experimental models, carcinogenic properties. One example is Mutagen X (MX), a chlorination by-product found at nanogram-per-litre concentrations but known for very strong mutagenic activity in bacterial test systems.
More chlorine does not automatically mean better water. Where suitable precursors are present, more chlorine and longer contact time can increase the formation of some DBPs. The objective is microbiologically safe water with the lowest unnecessary chemical burden.
Point-of-use adsorption filtration is therefore not only about taste and odour. Depending on the water and the filtration medium, it can be used to reduce residual chlorine and selected unwanted organic contaminants. Performance must always be related to the specific contaminant, medium, contact time, flow rate, incoming concentration and media capacity.
Myth 03 Hard water is only a cosmetic problem.
In reality
Limescale deposits on taps and in the kettle are a cosmetic issue. Deposits inside pipework, heat exchangers, and water heaters have a measurable effect on appliance lifespan and energy consumption.
Whether softening makes sense depends on actual water hardness, how water is used, and which appliances are at risk.
More detail
Water hardness is the concentration of dissolved calcium and magnesium ions. Above certain concentrations, these precipitate as calcium carbonate (scale) when water is heated.
Scale deposits reduce the thermal conductivity of heat exchangers — as little as 1 mm of scale increases energy consumption for heating measurably. Scale also accelerates wear of seals, valves, and connectors.
Softening by ion exchange is technically effective and well-established. The trade-off is sodium intake from the regeneration salt and the need to dose correctly — not every water requires the same approach.
Drinking water should not be softened to zero hardness. A certain level of mineral content is nutritionally appropriate and also affects taste.
Myth 04 Pharmaceuticals in water? The waterworks sorts that out.
In reality
Standard water treatment — coagulation, sedimentation, filtration, chlorination — was not designed to capture pharmaceutical residues. These are not removed completely by conventional processes.
Removing micropollutants reliably requires an additional treatment stage — adsorption, advanced oxidation, or membrane separation.
More detail
Pharmaceutical residues enter drinking water sources via treated wastewater, agricultural runoff, and direct discharge. Conventional waterworks treatment removes part of the load — but not all compounds, and not reliably at trace concentrations.
EU Directive 2024/3019 on quaternary wastewater treatment specifically targets the removal of micropollutants from treated effluent before it re-enters the water cycle. This is a regulatory acknowledgement that standard treatment is insufficient for these substances.
Adsorption on carbon nanotubes (ART CARBON) shows significantly faster kinetics compared to granular activated carbon — relevant where contact time is short, as it typically is in household under-sink filtration. TU Liberec independent tests: naproxen above 91 % removed at 10 seconds of contact; carbamazepine above 90 % at 30 seconds.
Myth 05 Microplastics are a negligible problem.
In reality
Microplastics have been detected in drinking water, bottled water, tap water, human blood, and tissue samples. Their long-term health effects are not yet fully established by research — which is itself a reason for caution, not complacency.
Microplastics above 0.1 µm can be captured by ultrafiltration membranes. Nanoplastics are a different technical challenge and require different approaches.
More detail
Microplastics are particles of plastic material below 5 mm in size. In water they originate from packaging, textiles (synthetic fibres), road wear, and the degradation of larger plastic objects.
Ultrafiltration membranes with a nominal pore size of 0.1 µm capture particles at the upper end of the microplastic range and larger. The IZS-M07 mobile unit, for example, uses a SiCBlox FX ceramic UF membrane — this captures microplastics above 0.1 µm but does not address nanoplastics, which require a different treatment approach.
Regulatory monitoring of microplastics in drinking water is in early stages in most countries. The absence of a regulated limit does not mean the issue is resolved.
Myth 06 Activated carbon is activated carbon. Filters work more or less the same.
In reality
The adsorption mechanism matters. Granular activated carbon works by pore diffusion — substances must migrate into the pore structure, which takes time. Carbon nanotubes adsorb on their outer surface, which is orders of magnitude faster.
At short contact times — typical in under-sink household filtration — the difference between materials is not marginal. It is the difference between effective removal and minimal effect.
More detail
Granular activated carbon (GAC) has a large internal surface area in its pore structure — but substances in solution must first reach that surface by diffusion, which is rate-limited. At normal household flow rates, the contact time in a small under-sink cartridge may be as short as 5–15 seconds.
ART CARBON uses carbon nanotubes immobilised on a carrier. The active surface is on the outside of the nanotube — immediately accessible. This means adsorption is effective even at very short contact times.
Independent tests at TU Liberec: at 30 seconds of contact, granular activated carbon removed 20 % of naproxen and 16 % of carbamazepine. ART CARBON removed over 90 % of both compounds at the same contact time. The difference in mechanism, not total surface area, explains the gap.
Myth 07 Reverse osmosis is always the best choice.
In reality
Reverse osmosis is a well-established and effective technology — the right choice in specific situations. It is not a universal answer for all water problems, and it comes with trade-offs that are often not mentioned upfront.
The right filter is the one that matches your water, your goal, and your operating situation — not the most technically advanced one available.
More detail
Reverse osmosis removes a very wide range of dissolved substances — including minerals, which is why remineralisation is frequently added as a downstream stage. It produces a concentrate stream (waste water) that must be managed. Flow rates are typically lower than unfiltered supply, which matters for certain applications. The membrane requires periodic replacement and the system needs regular maintenance.
RO is genuinely the best choice where broad-spectrum removal is required and where the trade-offs are acceptable — for example, in areas with severely contaminated source water, or specific food production applications where ultra-pure water is needed.
For removing chlorine taste, specific pharmaceuticals, or pesticides from otherwise compliant mains water, a targeted adsorption stage is often simpler, less expensive to run, and technically adequate.
Myth 08 A filter is safe even if water stands in it for a week.
In reality
A filter cartridge that has been standing with water in it for an extended period is a potential site of bacterial growth — not a neutral storage vessel. Stagnant water in organic filter media is a risk, not an inconvenience.
A filter used irregularly — at a holiday property, for example — needs a different management protocol than one in daily use.
More detail
Carbon-based filter media can support biofilm formation when water is stagnant — particularly in warm conditions. This does not mean that every filter is a hazard, but it does mean that a filter in a holiday property, used only at weekends or during seasonal visits, requires different thinking from a filter in permanent daily use.
Options for intermittent-use installations include filters with a smaller internal volume (less standing water), the use of materials with antimicrobial properties in combination, or a flushing protocol before the first draw of the day.
The risk is not theoretical — there are documented cases of bacterial counts increasing after stagnation periods in household filters. The relevant question is not "is this filter safe in general?" but "is this filter appropriate for how I actually use it?"
Don't know what's in your water? Start there, not with a filter.
Tell us where your water comes from, whether you have an analysis, and what concerns you about it. We will assess the situation first and only then recommend a next step — or tell you that a filter will not solve your problem.
The most common pattern: a household on mains water that tastes of chlorine, a well that has never been analysed, or a pool with recurring water quality problems. In all three cases, the right starting point is understanding what is actually there — not comparing filter specifications.
If you already have a water analysis, send it. If not, we can help you work out what to have tested.
The content on this page is informational and does not replace professional assessment of a specific water source. Statements are based on published technical references and practical experience; they do not constitute a guarantee of performance for any specific water. Technical details should be verified against independent test protocols before making decisions about water treatment investments.