Sinking a Water Borehole in Portugal in 2026: A Practical Guide to the 5 cv Rule, When a Prior Communication Replaces a Licence, the 100-Metre Spacing Limit, and the Fines for an Undeclared Well

You buy a place in the interior with a well in the yard, or a hectare of scrub where the neighbours all have boreholes, and someone tells you that water on your own land is your own business. In Portugal that is half true and the half that is wrong is expensive. Groundwater under private land can indeed be private water, but pulling it out of the ground is a regulated use of a water resource, and doing it without the right piece of paper is classed as a very serious environmental infringement.

This guide sets out what Portuguese law actually requires in 2026: when a simple communication is enough, when you need an authorisation, when a licence, what the 5 cv threshold really means, who is allowed to hold the drill, and what happens if an inspector arrives and your furo is not on any register.

The three titles, and which one applies to you

The Water Law, Lei n.º 58/2005 of 29 December, splits water into the public domain and private waters, and attaches a different instrument to each.

For almost every household, smallholder and rural buyer, the live rows are the last two. A borehole or dug well on your own land, feeding your own house, garden or animals, is an abstraction from private waters. The default is that it requires prior authorisation. The exception, and it is the exception most people fall into, is the 5 cv rule.

The 5 cv rule, precisely

Article 62(4) of the Water Law says that abstraction of private waters requires only a simple communication from the user to the body responsible for enforcing water-resource use, where the means of extraction do not exceed 5 cv. Cv is cavalo-vapor, the metric horsepower, and 5 cv is roughly 3.7 kilowatts. The test is the rated power of the pump, not the depth of the hole, not the volume you take and not the size of your land.

Two things commonly trip people up.

First, the exception is not unconditional. The same article ends by carving out any abstraction that the licensing authority characterises as having a significant impact on the status of the waters. If your borehole sits in a stressed aquifer, or a cluster of them does, the authority can pull it back into the authorisation regime regardless of pump size.

Second, a communication is not nothing. Failing to make the communication required by article 16 of Decreto-Lei n.º 226-A/2007 is itself a light environmental infringement. It is the cheapest offence in this guide, but it is an offence.

The 20-metre depth rule you will still be told about

Search in Portuguese and you will find, repeatedly, that a borehole needs a licence if the pump exceeds 5 cv or if the hole is deeper than 20 metres. That second limb comes from Decreto-Lei n.º 46/94, the previous regime, which Decreto-Lei n.º 226-A/2007 expressly repealed when it came into force in 2007. The depth threshold is not the operative test today. Older builders, older neighbours and a good deal of older online guidance have not caught up. Work from the 5 cv rule and from whether the authority has characterised your abstraction as significant.

The three phases of a borehole

Article 41 of Decreto-Lei n.º 226-A/2007 breaks any groundwater abstraction, whatever it is for, into three legally distinct phases. It is worth knowing them because your obligations attach to each separately.

1. Pesquisa (prospecting). The mechanical drilling, deepening and excavation done to establish whether water exists, in what quantity and at what quality.
2. Execução (construction). The works and technical procedures that turn a hole into something you can operate.
3. Exploração (operation). Actually taking the water, on the terms fixed in your title.

Prospecting and construction carry their own technical duties under article 41(2). The works must be carried out so as not to cause chemical or bacteriological pollution of the aquifer, whether by surface water and runoff seeping down the annulus or by mixing poor-quality groundwater with good. Artesian boreholes must be fitted with devices that stop water being wasted. If the prospecting comes up dry, or the borehole has to be replaced because of a technical error, the contractor, not you, is responsible for restoring the ground to its original condition, on the competent authority's instructions.

The 100-metre spacing rule

Article 41(2)(d) sets a minimum separation of 100 metres between the abstractions of different users drawing on the same body of groundwater. The regional water authority can set a different figure where there is a technical justification, in either direction. On a road of small rural plots this single rule decides more borehole applications than any other, and it is the reason a neighbour's borehole can block yours.

The 60-day completion report

Within 60 days of finishing the construction works, the user must file a report demonstrating that the works were properly executed, containing the elements set out in the implementing order made under article 14 of the same decree-law. Contractors will often prepare this. It remains the user's obligation, and it is the document that later proves your borehole was built to standard.

Who is allowed to do the drilling

You cannot hire a man with a rig. Firms carrying out groundwater prospecting and abstraction must themselves be licensed by the Agência Portuguesa do Ambiente (Portuguese Environment Agency, or APA) under Decreto-Lei n.º 133/2005 of 16 August, as amended by Decreto-Lei n.º 84/2011 of 20 June. The firm applies with a licence application, its technical director's name and curriculum vitae, an inventory of equipment and a list of the works it has completed over the previous five years. The licence runs for five years, and renewal must be requested 60 days before it expires. The fee for issuing that licence in 2026 is 2,293.74 euros, updated annually.

At the work site, the firm must display visibly its identity, its licence (alvará) number and, where one is legally required, the number of the water-resources title. If none of that is on display when the rig turns up on your land, the practical consequence is yours: the resulting borehole may be unregularisable.

How to file, and how long it takes

Requests for water-resource use that are not tied to an economic activity, which is where a private household borehole sits, go through the Recursos Hídricos module of SILiAmb, APA's integrated environmental licensing platform. APA, through its regional water administration for your river basin, is the competent authority.

Article 17 of Decreto-Lei n.º 226-A/2007 gives applicants for an autorização a valuable default: the request is tacitly granted if no express decision is notified within 45 days of it being filed. There are two exceptions, and both matter in rural Portugal:

• abstraction of water for human consumption; and
• abstraction in areas that, at the time of the request, are in a state of severe or extreme drought.

In those two cases silence means nothing and you must wait for a decision. Given that mainland Portugal entered meteorological drought this month after its driest July of the century, the drought carve-out is not theoretical. Where a decision is issued, the title itself must be sent to the user within 15 days.

If you want to drink it

Article 42 of the same decree-law draws a line most buyers do not expect. A private supply system producing water for human consumption may only operate on condition that public supply is impossible to access, and it is then subject to the full legal requirements for drinking water. If a mains connection is available at your boundary, the law does not contemplate you supplying your own household from a borehole instead, however good the water tastes. Using borehole water for irrigation, animals, a pool or washing down is a different question from using it as your household's drinking supply. Our guide to setting up utilities in Portugal covers the mains route.

Protection perimeters: the rule that can ban your borehole outright

Where a public-supply source has a protection perimeter delimited under Decreto-Lei n.º 382/99 of 22 September, the ground around it is divided into immediate, intermediate and extended zones, and the restrictions are published by government order.

• In the immediate zone, everything is prohibited except work to conserve, maintain or better operate the public abstraction itself. The land must be fenced and kept clear.
• In the intermediate zone, sinking a new borehole that is not for public supply is banned wherever a connection to the mains is possible, and any existing groundwater abstraction that is decommissioned must be cemented shut, not merely capped.
• In the extended zone, the same activity is conditioned rather than banned, alongside septic tanks, cemeteries, quarrying and fuel handling.

These perimeters are published as ordinary portarias and are easy to miss. Sixteen of them landed on a single day in August 2026, covering 23 sources in Alcácer do Sal, Sines and Santiago do Cacém. Before you buy rural land, ask whether any part of it falls inside a delimited perimeter, and get the answer in writing. In May, APA eased its outright drilling ban across most Algarve water bodies while keeping several frozen, which is a reminder that the answer changes with the aquifer and with the year.

What it costs to run

Holding a title triggers the Taxa de Recursos Hídricos (water resources charge, or TRH), set by Decreto-Lei n.º 97/2008 of 11 June, amended and republished by Decreto-Lei n.º 46/2017 of 3 May. It is built on the user-pays and polluter-pays principles and calculated from a formula with separate components for abstraction, for occupation of the state's public water domain, for discharge, and for the use of waters subject to public planning and management. It is calculated and paid through the TRH module of SILiAmb, on the basis of the data users report under their own self-monitoring obligations.

Separately, article 87 of Decreto-Lei n.º 226-A/2007 makes an administrative fee payable when you file a prior-information request or apply for a groundwater prospecting licence.

The fines, and why they are so large

Water offences are prosecuted as environmental infringements. Article 81 of Decreto-Lei n.º 226-A/2007 sorts them into three tiers, and the amounts come from Lei n.º 50/2006 of 29 August, the framework law on environmental infringements, as amended in 2015.

Now map the offences onto the tiers.

• Failing to make the article 16 communication is a light infringement. For a household, that is the 200 to 2,000 euro band.
• Using water resources without the respective title is a very serious infringement. So is breaching the conditions of the title you hold. For an individual acting negligently, that starts at 10,000 euros.
• Handling, depositing or storing harmful products near an abstraction or inside its immediate protection zone is also very serious, in three separate limbs of article 81(3). Fuel drums and manure heaps are exactly what this is aimed at.

Negligence and attempt are both punishable, so "I did not know" is a mitigating factor rather than a defence. Article 23 of Lei 50/2006 doubles the very-serious band at both ends where dangerous substances seriously affect health, the safety of people and property, and the environment. On top of the fine, the offender pays the cost of the inspection itself where there was no title or the title's conditions were breached, within 15 days of notification, and daily compulsory penalty payments of 50 to 250 euros for an individual can run for up to a month.

The amnesty that has already closed

Article 89 of Decreto-Lei n.º 226-A/2007 offered a two-year window from the regime's entry into force in 2007 for users without a title to come forward. Those who filed in time were immune from any fine for the untitled use until their title was issued, although the water charge was still due for the period. That window shut in 2009. There is no standing amnesty today, which is why an undeclared borehole discovered on a property purchase is a live liability rather than a formality.

APA's own guidance treats 1 July 2007 as the reference date: private boreholes and wells with extraction means not exceeding 5 cv are exempt from any title, and need to be communicated where the use began after that date. An old family well predating the regime sits in a different position from a hole sunk last year, which is precisely why the date the borehole was made is worth establishing in writing before you buy.

What This Means for You

• If you are buying rural property: put the borehole into the due diligence. Ask for the title or the communication receipt, the date the borehole was made, the 60-day completion report, the pump's rated power in cv, and a written statement on whether the plot falls inside any protection perimeter. Treat an unregistered borehole as a price issue, not a detail. Our property buying guide covers the rest of the conveyancing checklist, and the caderneta predial guide explains the tax record you will be reading alongside it.
• If you already own a well nobody ever declared: the exposure is real and it is in the very serious band. Take advice before you file anything, but do not assume that silence is safer than regularisation. The offence is continuing, and the amnesty is gone.
• If you are planning a new borehole: confirm the pump size first, check the 100-metre rule against your neighbours, use a firm licensed under Decreto-Lei n.º 133/2005, and keep every piece of paper the contractor generates.
• If you want to drink the water: establish whether a mains connection is available before anything else. If it is, the private-supply route is not open to you.
• If you farm, even at smallholding scale: the water file sits alongside the rest of the rural paperwork most newcomers discover late, from stock declarations to animal registers. Our guides to keeping bees in Portugal and to the winemakers' stock declaration show the same pattern: a small holding, a real register, and a fine for missing it.

Where to start

Read the pump plate. If it says 5 cv or less and the abstraction has never been characterised as significant, your obligation is a communication to APA through SILiAmb, and the cost of getting it wrong is the smallest band in the table. If it says more, or the borehole is new, or you intend to drink from it, you are in the authorisation regime, with a 45-day clock that does not run for drinking water or during severe drought.

In either case the document to find first is not the licence. It is the answer to a simpler question: does anyone in the Portuguese state currently know that your borehole exists? If the honest answer is no, that is the problem to solve, and it is cheaper to solve it before an inspector, a buyer's lawyer or a protection perimeter solves it for you.

This guide summarises the law as published and is not legal advice. Water-resource rules vary by river basin and by protection perimeter; check your specific plot with APA's regional water administration or a Portuguese lawyer before drilling or buying.