---
title: "Germany's TrinkwV and DVGW W551, France and the Netherlands: European Legionella regimes compared to the UK"
source_url: https://legionella.io/articles/germany-trinkwv-france-netherlands-legionella-regimes-vs-uk/
canonical_url: https://legionella.io/articles/germany-trinkwv-france-netherlands-legionella-regimes-vs-uk/
pillar: "UK Legionella Law & Compliance"
summary: "How Germany's TrinkwV and DVGW W551, France's ECS rules and the Dutch priority-installation duties compare with the UK's risk-based Legionella regime"
primary_keyword: "TrinkwV DVGW W551"
date_published: 2026-06-27
date_reviewed: 2026-06-27
author: "Legionella.io editorial team (REMOTE TECH LTD)"
reviewed_against: "HSE L8 and HSG274 guidance"
region: "United Kingdom"
license: "CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Quote, adapt or republish with attribution to REMOTE TECH LTD and a link to source_url."
license_url: https://creativecommons.org/licenses/by/4.0/
---

# Germany's TrinkwV and DVGW W551, France and the Netherlands: European Legionella regimes compared to the UK

If you run sites in Germany, France or the Netherlands as well as the UK, the first thing that surprises a UK-trained estates lead is this: on the continent, a laboratory often samples your hot water on a fixed calendar whether or not your risk assessment asks for it. The UK does not work that way, and that single difference reshapes how you write a group policy.

The UK regime is outcome-led. ACoP L8 and HSG274 set a duty to assess and control risk, then let a competent person decide what monitoring and sampling that control actually needs [1][2]. Routine Legionella sampling of a hot and cold water system is not a blanket legal requirement here; it is one tool the risk assessment may call for, most often where temperatures cannot be relied on or where susceptible people are present.

Several continental regimes invert that emphasis. They keep the risk-management duty but bolt on prescriptive, periodic sampling with numeric action values fixed in law or technical standards. Same goal, different lever.

## The four regimes at a glance

The table below is a high-level map, not a compliance specification. Every threshold is hedged because the exact figures, the installations they apply to, and the review cycles are set by national instruments that change, confirm the current text in each country before you act on it.

| Jurisdiction | Primary instrument | Core philosophy | Routine sampling | Threshold logic |
|---|---|---|---|---|
| UK | ACoP L8 + HSG274 (risk-assessment duty) | Assess and control risk; method is the duty holder's to justify | Not mandatory by default; the risk assessment decides where and how often | No single legal action value; control is verified mainly through temperature and the written scheme [1][2] |
| Germany | Trinkwasserverordnung (TrinkwV), with DVGW W551 as the technical rule | Risk management plus a defined technical action value for larger systems | Periodic investigation for "large" hot-water installations, typically including commercially let property | A technical action value commonly cited at around 100 CFU per 100 mL triggers investigation and remediation |
| France | ICPE rubrique 2921 (evaporative cooling) and arrêtés on ECS (hot water) | Prescriptive periodic monitoring, tightest for cooling towers and high-risk premises | Mandatory periodic Legionella monitoring for registered cooling installations and many ECS systems | Defined target and action thresholds; exceedances trigger declared actions and, for cooling towers, reporting |
| Netherlands | Drinkwaterbesluit / Drinkwaterregeling | Risk analysis plus management plan for named "priority installations" | Periodic sampling required for priority installations (hospitals, care homes, hotels, campsites and similar) | An action value commonly cited at around 100 CFU per litre triggers measures |

The pattern is clear once you read across the row. The UK column is the only one where "how often do you sample?" has no statutory answer, it depends on what your assessment found. The other three carry a default cadence written into the rules themselves.

## Germany: the technical action value

Germany frames Legionella control through its drinking-water ordinance, the Trinkwasserverordnung, with the technical detail supplied by the DVGW worksheet W551. The duty falls on operators of larger hot-water installations, the kind found in apartment blocks, hotels, care settings and commercially let buildings rather than a single private dwelling.

Two features feel foreign to a UK reader. First, a defined size threshold decides whether the duty bites at all, based on storage volume and pipe content. Second, when sampling is required it is investigated against a technical action value, commonly cited at around 100 CFU per 100 mL. Cross that and the operator is expected to investigate the cause, inform the relevant parties and remediate, a sequence specified far more tightly than the UK's "your risk assessment decides" position. Confirm the current size thresholds, sampling points and action value against the TrinkwV and W551 themselves, as both have been revised.

## France: prescriptive, and split by system type

France runs two distinct prescriptive streams. Evaporative cooling systems sit under the installations classées regime (ICPE rubrique 2921), which imposes mandatory periodic Legionella monitoring, recorded control measures and reporting obligations, among the more demanding cooling-tower regimes in Europe. Domestic hot water (eau chaude sanitaire, ECS) in establishments open to the public and in healthcare is covered by separate ministerial orders setting monitoring frequencies and threshold values, with stricter expectations where vulnerable people are present.

For a UK estate, the practical jolt is that a French hospital or hotel may be obliged to sample its hot water on a fixed schedule and report against fixed values, regardless of how well its temperature regime performs. The "control by temperature, verify by exception" instinct that works in the UK is not, on its own, a French compliance position.

## The Netherlands: priority installations

The Dutch model, under the Drinkwaterbesluit and its regulation, hinges on the concept of a "priority installation" (prioriteitsinstelling): categories of building where the consequences of Legionella are judged high enough to warrant extra duties. Hospitals, care homes, hotels, guest houses, campsites, swimming facilities and similar premises typically fall in scope.

Those operators must produce a risk analysis and a management plan and carry out periodic sampling, measured against an action value commonly cited at around 100 CFU per litre. Note the unit: the Dutch value is expressed per litre, while the German action value is per 100 mL. That is not a rounding quirk. It is a genuine trap when someone compiles a group dashboard, because a number that looks ten times larger may simply be the same concentration in different units. Always carry the unit, not just the figure.

## What this means for a UK-anchored group policy

The temptation is to write one number into a global standard and be done. Resist it. The regimes do not share a single action value, a single in-scope-building definition, or a single sampling cadence, and the units differ. A group policy that says "sample hot water quarterly and act above X CFU" will be wrong somewhere.

The workable approach is to set a group minimum built on the common ground, a documented risk assessment, ownership, temperature control, record-keeping and verification, which every one of these regimes recognises and which the UK and international frameworks share [1][3][4], and then layer each country's prescriptive sampling and thresholds on top as local annexes. Your UK risk-based duty becomes the floor; the continental sampling calendars and numeric values become country-specific additions, not replacements. That way a German site's W551 investigation cadence and a French site's ECS schedule both sit inside one coherent system rather than fighting it.

This is a high-level orientation, not legal advice, and the national instruments named here are summarised, not reproduced. Each jurisdiction's duties are set by its own current law and technical standards and must be applied through competent, locally qualified advice for the specific building, a UK risk assessment does not transpose into German, French or Dutch compliance, and vice versa.

## FAQ

### Why doesn't the UK mandate routine Legionella sampling like France or Germany?

Because the UK regime is built on assessing and controlling risk rather than prescribing a fixed test schedule. ACoP L8 and HSG274 expect a competent person to decide whether sampling is needed, where, and how often, based on what the risk assessment finds, for example where temperatures are unreliable or susceptible people are present [1][2]. Sampling is a verification tool here, not a standing legal obligation.

### The German and Dutch action values look very different, are they?

Often they are closer than they look, because they are expressed in different units. The German technical action value is commonly cited per 100 mL and the Dutch per litre, so a figure that appears ten times higher can be the same concentration measured differently. Always record the unit alongside the number, and convert deliberately rather than comparing the bare figures. Confirm the current values against each national instrument, as both have been revised.

### Does a UK-style risk assessment satisfy a German or French site?

No. A competent UK risk assessment is excellent practice and covers much of the shared ground, but it does not discharge the prescriptive duties, the German TrinkwV/W551 investigation regime, the French ICPE and ECS monitoring, or the Dutch priority-installation sampling. Those require the country-specific actions, thresholds and reporting on top, applied through local competent advice.

### What should a multinational group standard anchor to?

Anchor it to the controls every regime shares: a documented risk assessment, clear ownership, temperature control, record-keeping and independent verification, principles common to the UK duty and to international guidance [1][3][4]. Then add each country's mandatory sampling cadence and numeric thresholds as local annexes, so the group minimum is the floor and national prescription is layered above it.

## Where to start

If you are pulling several countries into one programme, build a single matrix before you write any policy: one row per country, columns for the legal instrument, the in-scope building definition, the sampling cadence, the action value and its unit, and the reporting trigger. Fill it from the current national texts, not from memory or last year's audit. The gaps and unit mismatches that fall out of that table are exactly what a group standard has to reconcile.

## Related reading

- [ESGLI guidelines vs UK HSG274](https://legionella.io/articles/esgli-european-guidelines-vs-uk-hsg274-reconciliation/)
- [WHO Water Safety in Buildings vs UK ACoP L8](https://legionella.io/articles/who-water-safety-in-buildings-vs-uk-acop-l8-compared/)
- [ASHRAE 188 and Guideline 12 for UK teams](https://legionella.io/articles/ashrae-188-and-guideline-12-explained-for-uk-teams/)
- [ECDC, ELDSNet and UK reporting](https://legionella.io/articles/ecdc-eldsnet-travel-associated-legionnaires-vs-uk-reporting/)

## Sources

[1] HSE, ACoP L8 (2013), “Carrying out a risk assessment”, p.12. https://www.hse.gov.uk/pubns/books/l8.htm
[2] HSE, HSG274 Part 2 (2024), “Operation and inspection of hot and cold water systems”, p.70. https://www.hse.gov.uk/pubns/books/hsg274.htm
[3] ECDC, "Legionnaires' disease". https://www.ecdc.europa.eu/en/legionnaires-disease
[4] WHO, "Water safety in buildings". https://www.who.int/publications/i/item/9789241548106