Water, Drought and Property: What Buyers Need to Check Before They Sign

Published on: August 17, 2026

Last verified: 17 August 2026. Reservoir levels move seasonally and municipal restrictions change; the structural points are durable, the numbers are not.

Quick answer: Water is the only climate risk that is a continuous condition of a property being usable, and it is checkable in advance with specific documents. Establish the legal source of supply, get the last four water bills, and if there is a well, get its concession or registration number from the basin authority. In Spain all water including groundwater is public domain, wells drilled after 1 January 1986 fall under the modern concession regime, unregistered wells number in the hundreds of thousands and the legalisation risk passes to you as buyer. Spanish reservoirs recovered strongly through 2025 and 2026, which changes the headlines and not the structural position. In Chile, water rights are a separate tradable asset: buying the land does not buy the water.

Buyers checking climate risk on a foreign property look at flood maps, wildfire zones and insurance availability. Almost nobody checks the water.

This is the wrong way round. Flooding and fire are episodic risks that may never materialise. Water supply is a continuous condition of the property being usable at all, and in the markets where foreign buyers concentrate (Mediterranean Spain, the Greek islands, the Algarve, Morocco, coastal Chile) it is under structural pressure that will outlast any individual drought cycle.

It is also, unlike most climate risk, checkable in advance with specific documents. This guide sets out what to check and what the answers mean.

First, an honest status update

Coverage of Mediterranean drought peaked in 2023 and 2024 and has not caught up with what happened next.

Spain's reservoirs have substantially recovered. The system serving roughly six million people around Barcelona left drought status in April 2025, and Catalonia's reservoirs subsequently rose above 84%, the fullest of any Spanish region. Andalusia recovered to around 80% of capacity. The western Costa del Sol and Malaga city returned to normal water status, with pool filling, garden watering and ordinary use permitted. Barcelona's ornamental fountains were phased back on through 2025 and into 2026.

Pockets of restriction remain, targeted at specific municipalities rather than whole regions: as of mid-2026 a small number of inland Malaga towns still prohibited filling pools and watering gardens with mains water.

What this means for a buyer is not that the problem is over. It means the acute phase of one drought cycle has ended, and the structural position has not changed. Spain's national water stress is estimated at around 43%, well above Germany's 34% and Italy's 30%. Reservoir levels are weather. Aquifer depletion, allocation rules and the legality of your particular water source are structural, and they are what you are actually buying.

The checks that apply anywhere

Work through these before the binding contract stage, in this order.

1. What is the legal source of water for this property? Mains connection, private well, shared community system, cistern with tanker delivery, or a combination. Each carries a different risk and a different document.
2. If it is mains, is the connection actually in place and paid for? A property marketed as connected may have a connection point at the boundary and no contract, or a supply that was disconnected and requires reinstatement. Ask for the last four water bills in the seller's name. If they cannot produce them, that is the finding.
3. If it is a well, is the well legal? This is the big one and is covered in detail below.
4. Is the property in a declared drought or over-exploited zone? Basin authorities publish this. An aquifer formally declared over-exploited is subject to abstraction restrictions that bind current and future owners regardless of what the deed says.
5. What restrictions applied in the last three years, and to whom? Ask specifically about pool filling, garden irrigation and any per-person daily allocation. During Andalusia's worst period, parts of Malaga were limited to 160 litres per person per day. Restrictions of that kind are municipal and can return.
6. If you plan a pool, is a pool permitted, and can it be filled? Increasingly a separate question from whether you can build one. Several Spanish municipalities now require a water source declaration as part of pool permitting, requiring registered mains or a legal well.
7. What is the local supply infrastructure? Desalination capacity, reservoir count, inter-basin transfer dependence and treated-wastewater reuse all change a location's resilience. A coast with a working desalination plant is in a different position from one dependent on a single reservoir.

Spain: the well question

Spain is where the largest number of foreign buyers meet this issue, and its water law has a specific structure worth understanding.

All water in Spain, including groundwater, is public domain under the Water Law. Owning the land does not give you the water beneath it. Abstraction requires authorisation from the relevant basin authority, the Confederacion Hidrografica, or the equivalent regional water agency.

The critical date is 1 January 1986. Under the 1985 Water Law, only wells authorised after that date yield public waters under the modern concession regime. Wells predating it fall under a transitional private-waters regime, in several cases running until roughly 2036 to 2038 where administrative protection was granted. This is why the position on any given rural Spanish property depends heavily on when its well was drilled and whether it was ever declared.

The scale of the problem is enormous. Estimates of unregistered and illegal wells in Spain run into the hundreds of thousands, with some figures above 500,000. Academic surveys have found areas with more illegal wells than legal ones. Enforcement has intensified: the Guardia Civil's environmental branch (SEPRONA) conducts raids, over a thousand illegal wells have been closed in the Donana area alone, and basin authorities can seal a well from the opening of proceedings through to their conclusion.

What this means for you as a buyer: if you buy a property with an unregistered well, you inherit the legalisation risk. That is the standard advice from Spanish and Balearic property professionals, and it is correct. Specifically:

• Ask for the concession or registration document from the basin authority, by number.
• Check the Land Registry and Catastro entries for any recorded water rights.
• Have your lawyer put an express representation about the well's legal status into the purchase contract, with a remedy if it proves false.
• New wells require a concession, hydrogeological survey, and minimum separation distances (typically 25 to 50 metres) from other water sources and structures. This is a months-long process with no guaranteed outcome.
• Penalties for unauthorised abstraction include fines and sealing of the well.

The Balearics are a specific case. On Mallorca, Ibiza and Menorca, finca purchases frequently involve wells and cisterns, oversight is shared between the basin authority and the Balearic government, and unregistered wells are common in older rural stock. The standard local guidance is blunt about it: check during your Land Registry and Catastro research, and have it clarified by the notary in the purchase contract. The rest of the rural checklist is in the rural land trap.

Pools in Spain

Pool restrictions during the 2022 to 2025 drought were regional, then delegated to municipalities, then partially lifted, then reimposed in specific towns. That volatility is the point: a pool is not a permanent entitlement in a water-stressed Spanish municipality.

The exemption pattern that emerged is worth knowing, because it affects investment cases directly: hotel, campsite, sports club and municipal pools were generally exempted before private and community pools were. If your rental case depends on a private pool being fillable every summer, you are carrying a regulatory risk that a hotel operator is not. During the 2024 restrictions, Andalusian agencies reported holiday-rental bookings falling as European guests avoided properties with uncertain pool access.

Also note the tax consequence: adding a pool raises the valor catastral and therefore your annual IBI bill. Running costs are in the cost of a swimming pool abroad.

Other markets worth knowing

The Greek islands

Several Greek islands have no meaningful natural freshwater and run on a combination of desalination and tanker deliveries by ship. Small Cycladic and Dodecanese islands in particular depend on seasonal water shipments, and summer demand from tourism can outstrip supply capacity.

For a buyer this changes several things. Water cost per cubic metre can be a multiple of mainland rates. Supply interruptions in August are a normal operating condition rather than an emergency. A property with a functioning cistern (sterna) and a large storage tank has a real, quantifiable advantage over one without, and on some islands is effectively a requirement. Ask what happens in the second half of August, and ask a neighbour rather than the agent. Island specifics are in our Greek islands guide and the Cyclades guide.

Greece has also introduced a climate resilience levy on accommodation, covered in our tourist tax reference, which is a fiscal expression of the same underlying pressure.

Portugal

The Algarve has faced repeated drought declarations, with restrictions affecting agriculture, golf course irrigation and municipal supply. The region's structural position depends on a small number of reservoirs, desalination projects at various stages, and treated-wastewater reuse for irrigation. Golf-adjacent property is worth a specific question here, since golf irrigation is consistently among the first uses restricted and among the most politically contested. See the Algarve guide.

Morocco

Morocco has run a multi-year drought with dam storage at historically low levels, driving a large national programme of desalination and water-transfer infrastructure. For buyers in Marrakech, Agadir and the Atlantic coast, the questions are the same as in Spain but with less publicly accessible documentation: what is the source, what is the legal basis for abstraction, and what happens in a restriction. Do not assume that a well on a rural property near Marrakech carries a clear legal title to the water. Market context is in our Morocco guide.

Chile

Chile is the one market on this list where water rights are a separate tradable asset from the land. Under the historical water code, rights were granted separately and could be bought and sold independently of the property, which produced concentrated ownership and, in central Chile's long megadrought, acute rural shortages with communities dependent on tanker deliveries.

A 2022 reform to the water code changed the regime for new rights, prioritising human consumption and introducing time limits and use requirements, while existing rights were largely preserved. The practical consequence for a buyer is unchanged and absolute: in Chile, buying the land does not buy the water. Verify what water rights exist, whether they are registered, whether they attach to the property, and whether they are actually exercisable in a dry year. See our Chile guide.

How to price it

Water risk shows up in a property's value through four channels. All four are worth quantifying.

Usability. A house you cannot reliably supply is worth less than one you can, whatever the view.

Rental income. Restrictions on pools and gardens reduce short-let bookings, as Andalusian agencies documented directly in 2024. If your case depends on peak-summer occupancy, this is a revenue risk, not a lifestyle one.

Running cost. Tanker water, desalinated supply and rising tariffs are permanent operating costs, not one-offs. On a Greek island the difference over twenty years is material.

Exit. As disclosure norms tighten, an unregistered well or a supply with no legal basis becomes a defect the next buyer's lawyer will find. You want to find it now, at your leverage point, rather than discover it when you are the one selling.

Frequently asked questions

Is southern Spain running out of water?
No, and reservoirs recovered strongly through 2025 and 2026, with Catalonia above 84% and Andalusia around 80%. What is true is that Spain carries structural water stress well above the Western European norm, that aquifer depletion is a long-term problem largely driven by agriculture rather than housing, and that restrictions have returned repeatedly in past cycles and can return again.

Can I still fill a swimming pool in Spain?
In most of the Costa del Sol and Malaga as of 2026, yes; those areas are classified as normal water status. A small number of inland municipalities still restrict it. Rules are set locally, change with reservoir levels, and are not a permanent entitlement. Check the specific municipality, not the region.

How do I check whether a well is legal?
Ask the seller for the concession or registration document from the basin authority, verify it with that authority directly, and have your lawyer include an express contractual representation about the well's status with a remedy attached. If the seller cannot produce the document, assume it is not registered and price the legalisation risk.

Does a property with a well have an advantage in a drought?
Only if the well is legal and the aquifer is not formally declared over-exploited. Where an aquifer is over-exploited, abstraction restrictions bind all users regardless of their individual concession. An illegal well is a liability in a drought, not an asset, because that is exactly when enforcement intensifies.

Which climate risk should I check first?
For most Mediterranean and semi-arid purchases, water, because it is the only one that is a continuous condition of use rather than a probability. Flood, fire and insurance availability matter too and are covered in our other climate pages, but water is the one that determines whether the property functions in an ordinary August.

Keep reading on JanusHermes

Water is the cheapest due diligence on a Mediterranean purchase and the most commonly skipped. JanusHermes aggregates local agency listings across more than 50 countries in 11 languages, with the local agency's contact details on the listing.

For the rest of the climate picture, see the climate risk check before buying, the uninsurable property problem and cities that may become unlivable by 2050. For the markets named above, read the Costa del Sol guide and the rural land trap. Before you commit, see how to hire a real estate lawyer abroad.

This article is general information about water supply and drought risk in property purchases, not legal, technical or investment advice, and it creates no advisory relationship. Reservoir levels, municipal restrictions and drought declarations change seasonally, and well legalisation depends on facts specific to each parcel and basin. Verify the legal status of any water source with the relevant basin authority and an independent local lawyer, and obtain a technical report where the supply is private, before committing funds.

Primary sources: Spanish Water Law (Ley de Aguas) and the 1985 reform, including the 1 January 1986 dividing line for public and private waters; Confederaciones Hidrograficas concession and registration procedures; academic and NGO estimates of unregistered abstraction in Spain, including WWF's assessment of illegal water use and Real Instituto Elcano's analysis of Spanish water stress; Junta de Andalucia drought management commission decisions on pool filling and per-person allocations; Catalan Water Agency status declarations from April 2025 onwards; Govern de les Illes Balears and Balearic basin authority guidance on well legalisation; the Chilean Water Code and the 2022 reform prioritising human consumption and introducing time limits on new rights.

Figures as published; latest available as of August 2026.