Private well in Belgium: what you need to know

An old brick well at the bottom of the garden, a borehole for watering, or the only water source for the whole house: the same two questions always come up. What does the Region require? And can you drink the water? We went through the official pages of Wallonia, Flanders and Brussels to answer them simply.

A groundwater abstraction that is not suitable for drinking-water production and not intended for human consumption, with a capacity of no more than 10 m³ per day and 3,000 m³ per year, requires a Class 3 declaration. It is submitted to the municipality before operation begins and is valid for ten years. If the water is intended for human consumption, or the volumes are larger, other rules apply: your municipality will tell you which procedure to follow.

Anyone who uses water from a well, owner or tenant, is also liable for the tax on the discharge of domestic waste water. The Walloon Public Service (SPW) sends the form in January, and the declaration must be returned by 31 March of the following year. A meter is not compulsory if the well supplies only the home and its outbuildings: the tax is then based on a flat rate, according to the number of people in the household.

For a new borehole, the approved driller must notify the administration of the work at least two working days before it starts.

Every groundwater abstraction that is put into or taken out of service must be reported to the Flemish Environment Agency (VMM). An environmental permit is needed, unless the water is pumped by hand only, or used for household purposes at less than 150 m³ per year. Since 2017, wells may only be drilled by an approved drilling company.

A flow meter is compulsory in principle. The exemption for household use up to 150 m³ per year no longer applies to new installations since 1 July 2025, and will end for existing installations on 1 July 2035. From 500 m³ per year, a groundwater abstraction levy is added.

Brussels Environment makes permanent groundwater abstractions subject to an environmental permit: Class 1D up to 500 m³ per year, Class 2 from 500 to 30,000 m³. A compliant water meter is compulsory, and the volumes abstracted are declared every year by 31 January. The only exceptions are abstractions without a motorised pump and the occasional pumping of seepage water in a building that existed before 1 April 2019.

Clear water is not necessarily safe water. According to the VMM’s guidelines for private households, between 2014 and 2022 only 30% of private well water analysed at the request of the Flemish authorities met every standard, and 33% was judged unfit to drink.

Nobody will do it for you: Aquawal points out that for an individual well with no commercial, tourist or public use, the authorities are under no obligation to check the water. In Flanders, well water used for drinking, cooking or washing must be tested before first use, then at least every five years; the authorities recommend testing every year, especially for wells less than 10 m deep. A home that cannot be connected to the public network is entitled to one free analysis a year through the water company.

Have the analysis done by an approved laboratory. The basic parameters include bacteria (E. coli, enterococci, coliforms), nitrates and nitrites, lead, iron, ammonium, pH and conductivity. Iron and manganese are often natural; bacteria and nitrates tend to come from the surface: a septic tank, animals, manure or crops nearby.

A poorly sealed wellhead lets run-off water in; a clogged filter or a worn UV lamp no longer protects anything. The VMM’s guidelines note that additional treatment (softening, UV, filtration) may call for extra analyses. In Flanders, the indoor installation of a well that supplies drinking water has had to be inspected since 1 January 2021, and it must never be connected to mains water. Wherever you live, keep the two networks strictly separate.

After a dry summer like 2026, a well can also run low: we covered this in our article on low groundwater levels.

Check that your well is declared, reported or permitted as your Region requires, and keep the documents.

In Wallonia, return the declaration of abstracted water by 31 March.

If the water is used for drinking, cooking or washing, have it tested by an approved laboratory, ideally every year.

Test again if the water changes in taste, smell or colour, turns cloudy, or after a flood.

Keep the wellhead closed, clean and protected from run-off water.

Replace filters and the UV lamp as the manufacturer specifies, and keep your test results from year to year.

We install, maintain and repair well pumps, booster sets and water treatment systems throughout Belgium: filtration, softening, UV sterilisation, making well water drinkable. We always start by looking at the installation and reading the water analysis, then propose the treatment it justifies, no more, no less. If something breaks down, our emergency service is available 24/7 on +32 4 325 10 02.