Frequently asked questions

We combine public sources: CDC Travelers' Health, WHO/GLAAS reports, WHO/UNICEF Joint Monitoring Programme (washdata.org), EU Drinking Water Directive 2020/2184 and local water agencies where available. Without reliable data we mark 'unknown' instead of guessing.

Safe: tap water is generally drinkable. Caution: varies by region or utility; when in doubt, filter or bottle. Unsafe: don't drink without treatment. Unknown: insufficient reliable data — treat as potentially unsafe.

A hollow-fiber filter forces water through thousands of microscopic tubes (≤0.1 micron). It blocks bacteria (E. coli, Salmonella) and protozoa (Giardia, Cryptosporidium). Viruses are smaller; for high-risk areas combine with a UV pen or chemical purifier. Look for NSF/ANSI P231 or P248 certification.

In Belgium, the Netherlands, Germany and most of the EU: yes. Run the tap 30–60 s and use cold water. In agricultural regions, request your utility's annual report (nitrate <50 mg/L). When traveling in countries with unsafe tap water, use bottled or filtered only.

Per WHO and CDC: 1 minute of rolling boil kills virtually all pathogens. Above 2,000 m: 3 minutes. Boiling does not remove chemical contaminants such as lead, nitrate or pesticides — those require a suitable filter.

We review per-country status at least annually and after major changes (new CDC/WHO reports, EU directives, local incidents). Each page shows its last-updated date.