Safe water in Portugal: notices, drought and what to store

Short answer. In Portugal, when the health authority finds that tap water is a potential health risk, your water utility must cut or restrict supply and inform users within 24 hours, on its website and by other means ³. Phaenyx found no national register of these notices. Civil protection advises a reserve of water and canned food for two or three days ⁴. Portuguese cities face extremely high water stress ⁵.

How do I know if my tap water is unsafe?

Under Decree-Law 69/2023, when the health authority (autoridade de saúde) determines that drinking water is a potential danger to health, the water utility (entidade gestora) interrupts supply or restricts use, following the health authority's instructions ³. Within 24 hours, the utility, working with the health authority and the regulator ERSAR, must tell every user in the supply zone, through its website and other means, about the danger and its causes, the measures taken, the health authority's advice on drinking and using the water, and later that service is restored ³. If a failure persists despite corrective measures and the health authority restricts or prohibits supply for more than 24 hours, the utility must provide an alternative source of drinking water ³. These articles were left unchanged by the first amendment of the decree, Decree-Law 149/2026 of 24 July 2026 ⁷.

Phaenyx found no national register of these notices: check your water utility's website. ERSAR, the competent authority for drinking water quality, lets you look up the quality of tap water by municipality in mainland Portugal ¹²; the Azores have their own regulator ². See our Portugal alerts page, and read What to do during a boil-water notice and Do-not-drink notices.

How much water should I store?

The national civil protection authority (ANEPC) asks households to keep "uma reserva de água e alimentos enlatados, para dois ou três dias", a reserve of water and canned food for two or three days, without giving a quantity in litres ⁴. Phaenyx found no official national litres-per-person figure. Details are on our Portugal emergency supplies page; for a benchmark from other agencies, see How much water to store per person per day?.

Is Portugal short of water?

Yes, structurally. In WRI's Aqueduct 4.0 model, the median of Portuguese cities (weighted by population) 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 ⁵. These are city medians: a given town or river basin can sit higher or lower.

The weather institute IPMA tracks meteorological drought with the PDSI index. It reports that between late August and late September 2026 the drought worsened very significantly in mainland Portugal, with weak to moderate drought replacing normal conditions in the North and Centre, and moderate and severe drought spreading in the South, especially inland ⁶. For household steps, see Drought preparedness.

What if I have a private well?

Decree-Law 69/2023 does not cover private supplies serving fewer than 50 people or under 10 m³ a day on average, unless the water is supplied as part of a commercial, industrial or service activity ³. For those supplies, the health authority must inform the people affected that they are outside the decree, and of the measures needed to protect their health; it must advise them whenever a potential danger is identified ³. See Private well emergencies.

What should I do after a flood?

Follow the notices of your water utility and the health authority ³, and see Water safety after a flood. A household plan can keep your water reserve and local contacts in one place.

Frequently asked questions

Who warns me if Portuguese tap water is unsafe?

Your water utility, within 24 hours, working with the health authority and ERSAR ³.

How long can a water cut last before I get another supply?

If the health authority restricts or prohibits supply over a persistent failure for more than 24 hours, the utility must provide an alternative source of drinking water ³.

How much water does Portugal recommend storing?

A reserve of water for two or three days; the official leaflet gives no litres ⁴.

Where can I follow drought in Portugal?

On IPMA's meteorological drought monitoring page, updated with the PDSI index ⁶.

Sources

1. Entidade Reguladora dos Serviços de Águas e Resíduos (ERSAR) — Controlo da Qualidade da Água — https://www.ersar.pt/pt_o-que-fazemos_controlo-da-qualidade-da-agua.html (accessed 2026-10-27)
2. Entidade Reguladora dos Serviços de Águas e Resíduos (ERSAR) — Qualidade da água – Pesquisa por concelho — https://www.ersar.pt/pt_consumidor_qualidade-da-agua_pesquisa-por-concelho.html (accessed 2026-10-27)
3. Diário da República (Presidência do Conselho de Ministros) — Decreto-Lei n.º 69/2023, de 21 de agosto (Diário da República, 1.ª série, n.º 161) — https://files.diariodarepublica.pt/1s/2023/08/16100/0001000073.pdf (accessed 2026-10-27)
4. Autoridade Nacional de Proteção Civil / Associação Portuguesa de Seguradores — Sismos: Prepare-se e Proteja-se — https://prociv.gov.pt/media/ovjbpe1c/sismos-prepare-se-e-proteja-se.pdf (accessed 2026-10-27)
5. World Resources Institute (WRI) — Aqueduct 4.0 (water stress, 2050 projection and drought risk) — https://www.wri.org/aqueduct (accessed 2026-10-27)
6. Instituto Português do Mar e da Atmosfera (IPMA) — Monitorização da Seca Meteorológica (índice PDSI) — https://www.ipma.pt/pt/oclima/observatorio.secas/ (accessed 2026-10-27)
7. Diário da República (Presidência do Conselho de Ministros) — Decreto-Lei n.º 149/2026, de 24 de julho (first amendment of Decreto-Lei n.º 69/2023) — https://files.diariodarepublica.pt/1s/2026/07/14200/0000500018.pdf (accessed 2026-10-27)