Read the full report on the NVWA website. The text has been written in accordance with Dutch legislation.

A recent compliance survey by the Netherlands Food and Consumer Product Safety Authority (NVWA) has revealed a striking gap between everyday practice in greenhouses and the legal framework governing the use of biocides. The results highlight the urgent need to treat irrigation water using a fully compliant method and the consequences of failing to do so.

What did the NVWA inspection reveal?

In 2025, the NVWA carried out a compliance audit at 29 randomly selected tomato growers in the Dutch greenhouse horticulture sector. The results were alarming: 90 per cent of the farms inspected were not complying with the legal regulations governing the use of biocides. Of the 29 inspections, 26 were found to be non-compliant and only three farms passed the inspection. A total of 87 breaches were identified.

Notably, all the farms where breaches were found were affiliated with one or more private quality schemes and held certifications. Paper compliance therefore offers no guarantee of correct practice on the work floor.

The most common violations

The NVWA has categorised the violations into six types. The three most common are directly relevant to anyone who disinfects irrigation water:

Incorrect use of disinfectants

In 23 of the 29 inspections, it was found that growers were not complying with the conditions for the use of disinfectants. A common example: hydrogen peroxide-based disinfectants (stabilised with silver) were being continuously dosed into the irrigation water system leading to the plants, even though this is explicitly prohibited. This treatment is intended for removing biofilm from water pipes, after which the system must be flushed with drinking water.

Sodium hypochlorite and chlorine dioxide were also used incorrectly on several occasions: these substances must not be added to the irrigation water during cultivation, due to the risk of residues in the crops and environmental damage caused by leakage.

Use of unauthorised biocidal products

During 16 inspections, the NVWA found that biocides were being used without a valid authorisation. In ten cases, this involved hydrogen peroxide without a biocidal product authorisation, used to combat biofilm in water pipes via continuous dosing. The NVWA also found that distributors actively recommend this practice, partly because unauthorised products are cheaper. The distributors concerned have been reported to the Human Environment and Transport Inspectorate (ILT).

In addition, plant protection products were used as biocides, authorisations from other countries that are not valid in the Netherlands were utilised, and an in-situ biocide based on an active substance not approved in the EU was even detected.

Incorrect registration

During six inspections, it emerged that the use of biocides had either not been recorded at all or had been recorded incorrectly. In some cases, biocides were recorded as fertilisers: a breach which, following an NVWA inspection, leads directly to a report of findings and possibly a fine.

The consequences: enforcement and fines

The NVWA has taken the following actions:

• Drawn up 26 reports of findings, which form the basis for a fine or other measure.
• Issued 7 official warnings.
• Launched a criminal investigation into contractors who allowed staff to remain in the area whilst the greenhouse was being disinfected with formaldehyde.
• Forwarded several reports to the ILT and the Labour Inspectorate.

The NVWA will take these results into account when setting up future risk-based supervision of the use of biocides in the agricultural sector. More inspections in the greenhouse horticulture sector are therefore to be expected.

How Watter helps you remain fully compliant

The NVWA’s findings highlight where things go wrong: growers use the wrong products, apply them incorrectly, or fail to record their use. Watter has been designed to prevent precisely these problems.

Approved biocide, PT4 (water systems)
Watter works on the basis of hypochlorous acid (HOCl), which has been scientifically tested under product type 4 (disinfection of water systems in the food sector). The product fully complies with the European Biocidal Products Regulation.

On-site installation by our own technicians
The Watter system is not simply delivered and left with you. Our technicians install the system on site and provide advice on the correct dosage. This ensures that the product is used as required by law and not in a way that leads to residues or incorrect use.

No more incorrect record-keeping or misuse
Watter helps you to prevent incorrect record-keeping by providing you with a disinfection solution that is fully and correctly registered. This helps you avoid the situation found in 20.7% of the growers inspected: missing or incorrect records, which lead directly to enforcement action during an inspection.

Conclusion: compliance is no coincidence

The NVWA inspection makes it clear that compliance with the biocidal products regulations in tomato cultivation cannot be taken for granted. Even certified businesses have committed breaches that could lead to fines, criminal investigations and reputational damage.

Watter offers tomato growers an integrated solution: an approved disinfectant for irrigation water, professional bespoke installation, and technical support to prevent incorrect use. This ensures you are prepared for the next NVWA inspection.