Heating Oil Leaks in Belgium: Households Left Alone to Face a Financial Nightmare

Published on 5/4/2026 · by Régis Demeulenaere

A Normalised Risk with Devastating Consequences

Every winter, countless Belgian families switch on their boilers with no idea of the danger sleeping beneath their basement or garden. A heating oil tank — whether above or below ground — ages. It corrodes. And statistically, more than 3% of all heating oil tanks will develop a leak at some point, most often due to rust or an incident during refuelling.

When a leak occurs, the oil seeps silently into the soil. It migrates downward, contaminates groundwater, sometimes reaches the foundations of neighbouring properties, and releases volatile compounds that can penetrate homes through their foundations — posing a serious health risk to residents. The pollution does not stop at property boundaries.

The cost of remediation is staggering. According to industry specialists, the average cost of soil decontamination following a heating oil leak is around 70,000 euros, and can far exceed that figure when contamination spreads to neighbouring plots or reaches the water table. In the most severe urban cases, the bills run into several hundred thousand euros.

Insurance Policies With Glaring Gaps

Faced with this risk, one might assume that households are well protected. The reality is far grimmer.

In Belgium, two types of insurance cover can theoretically apply: fire insurance and civil liability. But standard home insurance policies are far from offering adequate protection. In most cases, the "fire" guarantee only covers a limited amount, often capped at 10,000 euros — a pittance compared to a decontamination bill that can be ten times higher.

Civil liability, for its part, only kicks in when the pollution affects a third party, such as a neighbour. It does not protect the homeowner for damage on their own land.

Worse still: if the tank has not been inspected and certified in accordance with regional regulations, insurers may simply refuse to cover the damage. In Wallonia, tanks of more than 3,000 litres must be periodically checked by an approved technician. Tanks below 3,000 litres are subject to no inspection requirement whatsoever — yet they represent the majority of residential installations, left entirely without a regulatory safety net.

Specific soil remediation insurance policies do exist, such as the one offered by KBC, which covers up to 60,000 euros. But they remain largely unknown to the general public, and many homeowners simply never take one out — for lack of information.

Public Support: A Lifebuoy That Is Far Too Small

In response to the shortcomings of the insurance sector, public mechanisms have been put in place. The main one is the Promaz fund, a government-approved sectoral non-profit financed by a levy of one cent per litre of heating oil sold. Its mission: to intervene financially and operationally in the remediation of soils polluted by leaking heating tanks.

Promaz can cover part of the remediation costs, up to a ceiling of 200,000 euros for residential buildings and 100,000 euros for other types of buildings. In theory, that sounds reassuring. In practice, several significant limitations apply.

First, costs systematically remain at the homeowner's expense: administrative fees of 30.25 euros excluding VAT, plus management fees of 10% of the total works cost, capped at 500 euros for residential properties. And crucially, Promaz does not intervene in cases already covered by an insurance policy — which can create complex grey areas.

On top of that, the timelines are long. Assembling a file, conducting expert assessments, carrying out soil studies and remediation works: a heating oil disaster can keep homeowners tied up for months, sometimes years, in an exhausting administrative process.

Finally, the fund's financing itself raises concerns. Fed by a levy of just one cent per litre sold, it faces a double challenge: a rising number of intervention cases on one hand, and an energy transition that is progressively reducing heating oil sales on the other. Less oil sold means less revenue for the fund — at the very moment when the number of ageing or abandoned tanks is likely to grow as oil heating is phased out.

An Energy Transition Leaving Households in the Dark

The situation is all the more worrying as Belgium's regions are accelerating the phase-out of heating oil. In Wallonia, the installation of new oil boilers in new-build properties has been banned since 1 March 2025. For existing buildings, the replacement of old oil boilers will be prohibited no later than 1 January 2026.

This transition, though environmentally necessary, creates new responsibilities for homeowners. An abandoned and untreated tank is a ticking time bomb for soil pollution. Neutralisation or complete removal is legally required — and costly. Many households, already forced to invest in a new heat source, find themselves simultaneously having to manage their old installations within tight deadlines and without adequate financial support.

The Social Heating Fund can help lower-income households cover their heating oil bills (income ceiling set at 24,814.75 euros gross annual income in 2025–2026), and the federal government had introduced a 300-euro heating oil cheque during the energy crisis. But that cheque has not been available since April 2023, and no new federal energy subsidy is planned for the winter of 2025–2026.

What Needs to Change

Experts are unanimous: prevention remains the best remedy. A tank inspection costs between 100 and 200 euros — a negligible sum compared to a remediation bill. Yet thousands of tanks across Belgium have never once been inspected.

To better protect households, several avenues deserve serious consideration:

Making tank inspections mandatory regardless of capacity, particularly in Wallonia where tanks under 3,000 litres escape all regulation;
Better informing homeowners about specific soil remediation insurance, which remains far too little known;
Strengthening the financing of Promaz so that the fund can meet the foreseeable rise in claims linked to ageing tanks;
Establishing a financial support framework for households that must simultaneously switch to a new heating source and neutralise their old tank.
Until these reforms materialise, thousands of Belgians are sleeping on a risk they did not choose — and one they are, all too often, unable to face alone.

Sources: Promaz (promaz.be), Environment Wallonia, Sol-Ex, KBC Insurance, Social Heating Fund, aide-sociale.be, Test-Achats