Spain's drought phases: reservoir levels, alerts and who decides

Key rules

• Levels: Spain's drought plans use four levels, in this order: normalidad, prealerta, alerta and emergencia.
• Who declares: Your basin authority or regional water authority declares the level, depending on where you live.
• Town halls: Your town hall can add stricter rules than the basin or regional decree, but cannot relax them.
• Local check: Thresholds and measures differ by basin, region and town, so check the rules for your address.

The four levels

Spain's drought plans use four levels, in this order: normalidad, prealerta, alerta and emergencia. Each level is set for a water system, not for the whole country, so two neighbouring areas can be at different levels.

• Normalidad: no drought or shortage. Water is managed as usual.
• Prealerta: an early warning that a drought may be starting. Expect monitoring, awareness campaigns and requests to save water voluntarily.
• Alerta: a confirmed moderate drought. Authorities act to cut demand and reinforce supply, and some restrictions begin.
• Emergencia: severe drought. Restrictions are mandatory, exceptional measures apply and drinking water for homes comes first.

How a level is chosen

Each water system has indicators that combine into a score between 0 and 1. They draw on reservoir storage, underground water levels, river flows and accumulated rainfall. As a rough guide, a score of about 0.5 or above is normalidad, 0.5 to 0.3 is prealerta, 0.3 to 0.15 is alerta, and below 0.15 is emergencia. The exact indicators and thresholds differ between systems, so the plan for your basin has the real figures.

Who declares the level

It depends on where you live.

• Large river basins run by the state (Tajo, Ebro, Júcar, Segura, Guadalquivir, Duero, Guadiana): the river basin authority, called the confederación hidrográfica, checks the indicators every month. Its president declares the level. Extraordinary measures go through the national government, overseen by the Ministry for the Ecological Transition.
• Internal basins run by a region (for example Catalonia, the Basque Country, Galicia-Costa, parts of Andalusia, the Balearics and the Canaries): the regional water authority acts. In Catalonia, the Agència Catalana de l'Aigua declares the level and the regional government approves restrictions by decree. Catalonia uses its own names for its levels.

Your town hall can be stricter

Your town hall controls the drinking water in your town. It can issue a bando, a council notice, with tougher rules for its own network, such as bans on watering or filling pools. It must respect the basin or regional decree above it, and its measures must be reasoned and proportionate. Rules therefore differ from town to town, even inside one basin.

What it means at home

• Prealerta: mainly awareness and voluntary saving.
• Alerta: usually bans on watering gardens and washing cars or streets with drinking water, and limits on filling pools and ornamental fountains.
• Emergencia: stronger limits, including lower water pressure or fewer supply hours. In 2024, Catalonia's emergency decree capped use at about 200 litres per person per day, tightening in deeper emergencies.

Check your current level

Levels change as reservoirs fill or fall. The Ministry for the Ecological Transition publishes a monthly drought indicators report listing each system's level. Use it, then check your region's decree and your town hall's notices. The process and checklist below walk you through this.

Find the water rule that applies to your address

• Find your river basin (demarcación hidrográfica) on the Ministry for the Ecological Transition's map viewer: First, before you look for any rule. Switch on the layer 'Demarcaciones hidrográficas', enter your address or town and read the basin shown. Towns near a boundary can be split between basins, so confirm on the viewer.

• Check the basin authority that covers you: Right after you know your basin. Catalonia's internal basins fall under the Agència Catalana de l'Aigua. Other regions have their own agencies, such as Galicia-Costa, the Balearics and the Canary island councils.

• Find the current drought level for your basin: Once you know the basin authority. Search its website for 'sequía' or 'Planes especiales de sequía' and read the latest follow-up report. The Ministry also publishes a monthly drought and scarcity indicators report and a weekly reservoir bulletin.

• Look up your region's drought decree: After you know the level. Regional decrees appear in the region's official gazette, such as DOGC in Catalonia, BOJA in Andalusia, DOGV in Valencia, BORM in Murcia and BOIB in the Balearics. Check the date on the entry, because decrees are replaced when the level changes.

• Check your town's own rules or bando (a council notice): Last, because a town can set stricter rules than the basin or region for its own water network, such as bans on watering or filling pools. Look on the council website under its online office, notice board or 'bandos' section, in the provincial bulletin, and on your water utility's site.

• Call the town hall or water utility if you find nothing: If the websites are unclear or out of date. Ask the ayuntamiento, the utility's customer line or the local police, and ask for the date and reference of the bando.

Checklist

• Identify whether your area is in a state-managed river basin or an internal basin run by your region.

• Open the latest monthly drought indicators report from the Ministry for the Ecological Transition and find the level of your water system: normalidad, prealerta, alerta or emergencia.

• Check your basin's drought plan for the index thresholds that apply to your system, as they differ between systems.

• Find out which authority declares the level for you: the basin authority's president in a state-managed basin, or your regional water agency in an internal basin.

• Note what your current level usually means for a household: only voluntary saving in prealerta, bans on watering gardens and washing cars or streets with drinking water in alerta, and pressure or supply-hour cuts in emergencia.

• Ask your town hall whether it has issued a stricter notice (bando) for your water network.

Frequently asked questions

How is the drought level for a basin worked out?

Each water system combines its indicators into one index between 0 and 1. Normalidad sits at roughly 0.5 or above, prealerta from about 0.5 to 0.3, alerta from about 0.3 to 0.15 and emergencia below about 0.15. The indicators use reservoir storage, aquifer levels, river flows and accumulated rainfall, and each system sets its own thresholds.

Does Catalonia declare drought levels the same way as other regions?

No, Catalonia's regional water agency (ACA) declares its own exceptionality scenarios, not a river basin authority. The Generalitat then approves restrictions by decree or resolution. Catalonia uses its own scenario names, and the Basque Country, Galicia-Costa, the Balearics and the Canaries also work through regional bodies.

Can my town hall ban things the basin decree allows?

Yes, your town hall can set stricter rules for its own water network, such as bans on watering or filling pools. It must respect the basin or regional decree above it, and its measures must be proportionate and reasoned. Look for a council notice (bando) or local ordinance.

Where can I see which areas are in drought now?

The Ministry for the Ecological Transition publishes a monthly drought indicators report that lists the level of each system. Most basins recovered after the wet 2025 and 2026 winter and spring, and Catalonia's emergency ended in 2025. Read the latest report for the current picture.