Infectious Diseases Control Act (Construction)

Infectious Diseases Control Act (Construction) - The Infectious Diseases Control Act (IfSG) is relevant to the construction and real estate sectors when it comes to drinking water hygiene in buildings. Section 37 of the IfSG requires operators of water supply systems to provide safe drinking water. For owners of apartment buildings and commercial properties, this results in specific testing and reporting obligations - particularly regarding Legionella in hot water systems.

Legionella Testing According to the Drinking Water Ordinance (TrinkwV)

The Drinking Water Ordinance (TrinkwV) - in addition to the IfSG - mandates regular Legionella testing for large-scale drinking water heating systems. A large-scale system is defined as a hot water system with a storage volume of 400 liters or more, or with more than 3 liters of pipe volume between the heater and the farthest tap. This typically applies to multi-family homes with three or more residential units and a central hot water supply, as well as office buildings, hotels, and all commercial properties with a hot water supply.

The testing must be performed every three years by a laboratory accredited according to DIN EN ISO/IEC 17025. The laboratory takes water samples at specified measurement points (heater outlet, circulation, draw-off points) and analyzes the Legionella content. If the technical action level (100 CFU/100 ml) is exceeded, countermeasures must be taken immediately and the public health department must be notified. The technical action level is significantly below the limit value of 1,000 CFU/100 ml-exceeding it is merely a signal to take action, not an immediate danger.

Obligations for Property Owners

Owners and managers are responsible as operators of the drinking water system. Their obligations include: regular Legionella testing (every three years), mandatory reporting of large-scale systems to the public health department upon initial commissioning, documentation of all test results and measures taken, immediate notification to the public health department if the action level is exceeded, and the elimination of contamination through appropriate measures.

Violations of the testing and reporting obligations can be punished as administrative offenses with fines of up to 25,000 euros-in cases of health damage, there is even a risk of criminal prosecution for bodily injury by omission. Property management companies that fail to arrange Legionella testing in violation of their obligations are civilly liable for any resulting damages.

Technical Causes and Prevention

Legionella bacteria thrive at water temperatures between 25 and 45 degrees Celsius. Stagnant sections in rarely used pipes (guest apartments, basement restrooms, outdoor faucets) as well as deposits and corrosion in old metal pipes promote their growth. Technical preventive measures include: Setting hot water storage tanks to at least 60 degrees Celsius, regularly flushing rarely used outlets, performing hydraulic balancing of the circulation line, and-in older buildings-replacing outdated galvanized pipes.

A hydraulically properly balanced hot water system, in which water circulates continuously at a sufficiently high temperature, offers the best protection against Legionella growth. For new construction and extensive renovations, we recommend having the drinking water system designed by a specialized contractor in accordance with DIN 1988.

Practical Tip for Property Owners in Nuremberg

We recommend that owners of multi-family homes in the Nuremberg metropolitan area schedule Legionella testing as a fixed item in their management calendar and commission an accredited laboratory to perform regular sampling. The Nuremberg Health Department conducts random inspections and ensures compliance with testing intervals. Older buildings with galvanized water pipes or rarely used taps pose a particularly high risk.

Renovating the hot water system is often more cost-effective than the follow-up costs of a Legionella outbreak: In addition to fines and civil liability, a confirmed outbreak incurs significant costs for immediate measures (thermal disinfection, end-of-line filters, usage restrictions) and subsequent remediation. We support our clients in systematically addressing Legionella protection as an integral part of professional property management.

Drinking Water Hygiene When Purchasing Real Estate

Anyone purchasing a multi-family residence should also assess the status of drinking water hygiene as part of the due diligence process. Relevant questions include: Is the most recent Legionella test available? Was the result normal? Is the system properly registered with the health department? Are there any requirements or outstanding reporting obligations? This information should be fully disclosed by the seller; malicious concealment of known testing obligations can lead to claims for damages.

When transferring rented properties, we also recommend conducting the Legionella test-provided it is due within the next 12 months-before the sale. This protects the buyer from an unexpected initial investment and strengthens confidence in the proper management of the property.

Frequently Asked Questions

As the owner of a two-family home, do I have to have Legionella testing performed?

No. The obligation to conduct regular Legionella testing applies only to large systems in buildings used for commercial or public purposes-typically those with three or more rented residential units and a central hot water supply. Owner-occupied single-family and two-family homes are exempt, even if they have a central hot water system.

Who bears the costs of Legionella testing?

The testing costs (approx. 150-400 euros per test) can be passed on to tenants as operating costs for rented properties, provided this is agreed upon in the lease agreement (§ 2 No. 2 BetrKV - Costs of Water Supply). The owner bears the costs of any necessary remediation.

What happens in the event of a Legionella outbreak?

If the action threshold is exceeded, the owner must notify the public health department, have a risk assessment conducted by a certified expert, and take countermeasures-e.g., thermal disinfection (flushing at a minimum of 70 degrees Celsius at every tap), replacement of pipe sections, or installation of end-of-line filters. Until the contamination is eliminated, the health department may impose usage restrictions, such as bans on showering.

Does the testing requirement also apply to commercial properties?

Yes. Office buildings, hotels, medical practices, and other commercial properties with hot water systems and showers are also subject to the testing requirement if the system is classified as a large-scale system. Stricter requirements apply in some cases to hotels and lodging facilities. For commercial properties, we generally recommend an initial assessment of the hot water system by a specialist firm for drinking water hygiene.

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