Improving water quality at home

January 23, 2026

I cannot drink my tap water in Italy. I, and so many others, do not like the taste. I live in Tuscia, a geological region that has arsenic and other natural contaminants in the ground, and that includes also uranium. One of our municipalities, Ronciglione, even had a water ban for tap water precisely because of that.

Even at the limits of the Drinking Water Directive, which is 10 microgram per L for arsenic, science reveals significant health risks. Long-term arsenic exposure can have serious health effects. It can increase the risk of cardiovascular disease, lung, and liver cancer.

Check the ECHA website for arsenic. Also more on arsenic and drinking water from WHO.

In my case, the exposure to arsenic comes not only from drinking water. It also comes from other sources like food, soils, and anything that has contact with water.

Some people drink locally tap water, God bless them. With 22 years of water pollution experience, I just can’t. I know how good water tastes: it tastes like nothing. But that is not what worries me. When tap water has issues, indirect exposure by bathing and food hygiene is also an issue. And that can be problematic, or for me, unsettling for arsenic. Arsenic is not what causes taste in my tap water. That is precisely why I am not happy with it. If there is a taste there that is a bit off, there must be other problems too. Even when the water is compliant with a Directive.

Reverse osmosis (RO) is the technology that sorts at home this type of pollution. Charged membranes, which use a significant amount of electricity to run, can separate metal from water. RO is energy-intensive, complex to implement, run, and keep at the utility level. But it works. See detail case and filtration choice manual here:

One thing I don’t like about RO at home filtration units is the generation of residual water. It produces 1/3 volume of water carrying precisely the stuff that the filter removed.

RO drinking water is operational in my region. It functions at the Drinking Utility levels. However, I have not figured out their operational coverage yet. My tap water tastes off. I often face water bans where I live. The massive local consumption of bottled water is also clear. I do not need to see operational data to know something is not working as it should.

The Compliance Illusion

Whoever claims producing drinking water is easy is either crazy or hallucinating. Our current regulatory framework, the European Drinking Water Directive (DWD), is a thorough compliance bar for chemical and microbiological pollutants. But when I see a value that is right at the limit, I am not happy.

My tap water has an arsenic level of 10 micrograms per L. The DWD says 10 is the limit. These numbers are often relative and arbitrary. Laboratory results oscillate within standard deviations that are acceptable for GLP standards. Yet, they are not acceptable for my health, my family, or my cooking.

I could bite the bullet and trust the authorities, but when I drink this water, my stomach reacts. Arsenic is often just a proxy for other contaminants. So, I had no option but to commission a private RO filtration unit.

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INLET TAP WATER IN MY KITCHEN

Arsenic in the outlet, quite good after Point-of-USE Filter

But, the final issue: pH outlet was 5.3, very acidic and undrinkable

My recent case study highlights a critical failure in the filtration market. The study shows a high-end system that effectively removed the arsenic. However, it rendered the water undrinkable due to a lack of local chemical calibration.

THE ISSUE: Technical Success, Functional Failure

I commissioned a Waterdrop Reverse Osmosis (RO) system to tackle the geological arsenic in the Tuscia region. The results revealed a complex chemical imbalance:

[Download the Full Case Study: Viterbo Arsenic & pH Matrix]

• Arsenic Removal: The system performed perfectly here, dropping levels from 10μg/L to undetectable.
• pH Destabilization: Because Viterbo’s “income water” is naturally acidic (pH 6.5), the RO process stripped the remaining minerals and crashed the pH even further.
• Metallic Leaching: The resulting water was so aggressively acidic it tasted like metal, potentially leaching chemicals from the system’s own plastic fittings.
• The Remineralization Myth: Adding generic salts back in (remineralization) cannot fix a fundamentally imbalanced source it only masks the chemical instability.

[Download the Full Case Study: Viterbo Arsenic & pH Matrix]

STRATEGIC ANALYSIS & B2B OPPORTUNITY

This failure proves that Point-of-Use (POU) filtration units aren’t just plug and play appliances. They need to be customized according to the inlet water, and this is something me, and the supplier, overlooked. Molecular defense mechanisms that require professional calibration. In this case, even I, an experienced water kiddo lost the mark. Tuscia tap water and the device were not a great match.

• Arsenic Threshold: 10μg/L (Legal Maximum ≠ Biological Optimum).
• Strategic Gap: Most companies lack the marketing and technical depth to explain how their systems adapt to varying “income water” profiles.
• The PFAS Edge: New Directive requirements for PFAS monitoring represent a massive market opportunity for technology providers who can offer adaptable, verified solutions.

METHODOLOGY: A Scientific Framework for Your Business

I use a rigorous protocol to ensure water systems actually perform in the field:

• Sensory & Lab Validation: I spent €200 on mass spec testing to move beyond manufacturer claims. Arsenic was out but outlet pH 5.3 was a disaster…
• Regulatory Alignment: I help B2B clients pivot to the new reality of the Drinking Water Directive and micropollutant monitoring.
• Economic Calculus: Switching from bottled water (at €90/month) to a calibrated system yields a €5,400 saving over 5 years and a massive reduction in plastic waste. Well not using the filter above, but my search continues.

Do you want the full case study or help with your water strategy? Need help telling your product stories?

Contact: projects@ana-almeida.com

#RegulatoryScience #WaterQuality #PFAS #B2BWaterSolutions