Short answer. In Belgium, warnings about unsafe tap water come from the company that supplies your address; Phaenyx found no national register. The SWDE, a Walloon distributor, posts notices online and red, orange or green notices in letterboxes 1; De Watergroep, in Flanders, posts current information under "Storingen en werken" 7. The National Crisis Centre (NCCN) advises planning 3 to 10 litres of water per person per day 3.
How do I know if my tap water is unsafe?
Phaenyx found no single national register of boil-water or do-not-drink notices in Belgium. Each water company informs its own customers with its own procedure, so know which one supplies your address.
SWDE (Wallonia). As soon as water is declared non-potable somewhere on its network, the SWDE publishes a notice under "Incidents & chantiers" with the area concerned, the severity of the pollution and the place where it provides drinking water instead 1. Notices also go into letterboxes 1:
| Notice | Meaning 1 |
|---|---|
| Red | The water is temporarily not drinkable, even boiled. Do not consume it. |
| Orange | The water is not drinkable but can be consumed if boiled. |
| Green | The incident is closed; the water is drinkable again. |
When water is not drinkable, the SWDE sets up drinking-water supply points, and its customer service can tell you where they are 1.
De Watergroep (Flanders). After maintenance work, which carries a risk of contamination, and while lab checks run (a few days), it advises boiling tap water for at least 5 minutes before drinking, cooking or brushing teeth; showering and washing need no boiling 7. Current information is under "Storingen en werken" on its website 7, which lists outages and works by municipality and postcode 2.
VIVAQUA (Brussels). VIVAQUA leaves a notice in letterboxes at least 72 hours before planned works in your street, but cannot always warn residents before emergency repairs. After any water cut, it advises purging your pipes by filling 2 buckets at the tap nearest your meter 8. Phaenyx found no public VIVAQUA page explaining how it announces a boil-water or do-not-drink notice.
For what to do under each kind of notice, read What to do during a boil-water notice and Do-not-drink notices.
How much water should I store?
The NCCN asks households to be self-sufficient for at least 72 hours and to plan 3 to 10 litres of water per person per day, of which an adult drinks 1.5 to 2 litres 3. Full figures are on our Belgium emergency supplies page; for storage, see How much water to store per person per day? and Water storage containers.
Is Belgium short of water?
On paper, yes. In WRI's Aqueduct 4.0 model, the population-weighted median of Belgian cities falls in the "extremely high" category for current water stress, stays "extremely high" in the 2050 business-as-usual projection, and is "medium" for drought risk 4. These are city medians: a given town or river basin can sit higher or lower.
In Flanders, the authorities call on people to use water sparingly during drought. The provincial governors decide drought measures in their province, and mayors can, for example, ban taking water 5. The Flemish framework for priority water use states that public health must never be put at risk: people must always have tap water for essentials such as drinking, cooking and washing 5. The VMM publishes the current state of tap-water supply 6. Phaenyx found no equivalent official restrictions page for Wallonia or Brussels. For household steps, see Drought preparedness.
What if I have a private well?
Phaenyx found no official Belgian guidance for households on testing a private well. For what to do if a well may be contaminated, see Private well emergencies.
What should I do after a flood?
The SWDE lists floods among the incidents that can make tap water temporarily unfit to drink 1: follow your water company's notice before drinking it, and see Water safety after a flood. A household plan can keep your water stock and your distributor's contact details in one place.
Frequently asked questions
What does an orange SWDE water notice mean?
The water is not drinkable as it comes, but it can be consumed once boiled 1.
Who tells me if I must boil my water?
Your water company. The SWDE publishes notices online and in letterboxes 1; De Watergroep posts current information under "Storingen en werken" 7. Phaenyx found no national register.
How much water for a family of four?
At 3 to 10 litres per person per day 3, 72 hours makes 36 to 120 litres (our calculation).
Sources
- Société wallonne des eaux (SWDE) — Qualité de l'eau : eau non potable — https://www.swde.be/fr/qualite-de-leau-eau-non-potable (accessed 2026-10-27)
- De Watergroep — Storingen en werken — https://www.dewatergroep.be/nl-be/storingen-en-werken (accessed 2026-10-27)
- Centre de crise National (NCCN), SPF Intérieur — Un kit d'urgence à la maison — https://centredecrise.be/fr/que-pouvez-vous-faire/preparez-un-kit-durgence/un-kit-durgence-la-maison (accessed 2026-10-27)
- World Resources Institute (WRI) — Aqueduct 4.0 (water stress, 2050 projection and drought risk) — https://www.wri.org/aqueduct (accessed 2026-10-27)
- Vlaamse overheid (Vlaanderen.be) — Droogtemaatregelen — https://www.vlaanderen.be/droogtemaatregelen (accessed 2026-10-27)
- Vlaamse Milieumaatschappij (VMM) — Drinkwater – Feiten & cijfers — https://www.vmm.be/water/drinkwater (accessed 2026-10-27)
- De Watergroep — Veelgestelde vragen – Drinkwaterkwaliteit (kookadvies) — https://www.dewatergroep.be/nl-be/drinkwater/veelgestelde-vragen/drinkwaterkwaliteit?vraag=kookadvies (accessed 2026-10-27)
- VIVAQUA — Un chantier dans votre rue — https://chantiers.vivaqua.be/ (accessed 2026-10-27)
Turn this into action
Your plan for Belgium, worked out for your household.
- Water, food and equipment counted for each person and pet
- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- Société wallonne des eaux (SWDE) · Qualité de l'eau : eau non potable checked 2026-10-27
- De Watergroep · Storingen en werken checked 2026-10-27
- Centre de crise National (NCCN), SPF Intérieur · Un kit d'urgence à la maison checked 2026-10-27
- World Resources Institute (WRI) · Aqueduct 4.0 (water stress, 2050 projection and drought risk) checked 2026-10-27
- Vlaamse overheid (Vlaanderen.be) · Droogtemaatregelen checked 2026-10-27
- Vlaamse Milieumaatschappij (VMM) · Drinkwater – Feiten & cijfers checked 2026-10-27
- De Watergroep · Veelgestelde vragen – Drinkwaterkwaliteit (kookadvies) checked 2026-10-27
- VIVAQUA · Un chantier dans votre rue checked 2026-10-27