Legally compliant planning and operations for drinking water installations

Importance of generally recognised codes of practice for planning and operations

Section 13 of the German Drinking Water Regulation states the following: As a minimum requirement, water supply systems must be planned in accordance with the generally recognised codes of practice. These systems are also to be operated at least in accordance with these codes.

The term ‘generally recognised codes of practice’ is understood to mean technical rules or methods that are scientifically sound, and which are proven and known to practitioners working in the industry. Collectively, these constitute the definitive technical standard and are thus seen as legally binding. Such rules or methods include formal (e.g. DIN) standards and guidelines (e.g. VDI guidelines) as well as accident prevention regulations (e.g. DGUV regulations).

Important: Compliance with these rules is not a mere recommendation, but the basis for professional planning, execution and maintenance, and the safe operation of the drinking water installation.

Why deviations can become critical

Deviations from the generally recognised codes of practice are a legal minefield. With drinking water installations in particular, deviations can become associated with hygiene risks and therefore pose a serious threat to user health. Any deviation is therefore only conceivable in truly exceptional cases: such a deviation must be contractually agreed, of at least equal technical value and demonstrably safe. The client is always responsible for providing full details and supporting evidence.

Important: No deviation is allowed if it could lead to health risks (even if only in theory).

A clear recommendation for practice: the generally accepted codes of practice need to be followed to the letter. Any deviation can potentially result in legal, hygiene and health risks.

Alongside the generally recognised codes of practice, a concept known as ‘public safety obligations’ also applies to the operation of drinking water installations.

In a nutshell, this principle states that anyone who creates or operates a potential hazard is required by law to take the necessary and reasonable steps (safety precautions) to prevent any loss or injury to others.

A failure to do so can provide grounds for claims pursuant to section 823 of the German Civil Code (BGB).

Identifying and avoiding hazards

Public safety obligations require steps to be taken to avoid identifiable hazards for users. Operators of drinking water installations must therefore keep an eye on potential risks and implement suitable protective measures. Such risks include hygiene risks due to stagnation or unsuitable materials and risks to users from excessively hot water.

Important: Potential risks should already be accounted for at the planning stage. Planners should advise operators about these potential risks and propose suitable measures.

Operations, maintenance and record-keeping

Public safety obligations extend beyond simply accounting for risks during planning activities. During day-to-day operations, operators must also ensure that the drinking water installation does not create hazards for its users. Key activities here include regular inspection, maintenance and record-keeping.

Important: The generally recognised codes of practice are also a benchmark for operation and maintenance activities. These codes set out the measures that are required to keep operations safe and hygienic.

The basic precondition for maintaining drinking water quality is the regular exchange of water. VDI 6023 states that this must take place at least once every 72 hours.

In buildings used by the public like schools or offices, long weekends, public holidays or summer holidays can easily lead to problems with stagnation in the piping. If the same water stays in the piping for too long, however, this can favour the spread of bacteria like Legionella. To prevent this from happening, the regular exchange of water across all tapping points must be assured.

Alongside the regular exchange of water, the water temperature is another key factor that should be controlled to prevent the excessive growth of bacteria. Temperatures required: cold water 25 °C and hot water >55 °C

Using suitable materials and products

The materials used in the installation also have an impact on drinking water quality. Metals, plastic parts and mineral deposits can all change the properties of the drinking water and negatively affect its hygienic safety. Accordingly, all of the materials and products used must be suitable and approved.

Relevant legislation includes sections 14 and 15 of the German Drinking Water Regulation, which set out requirements for installation materials that come into contact with drinking water.

Important: As noted in technical codes like DIN EN 806-2, DIN 1988-200 and DVGW W 534, the choice of suitable materials also depends on the properties of the local drinking water. Planners should therefore consult the details provided by the water utility and specify suitable materials and components early on.

Anti-scalding protection and safe usage

According to DIN EN 806-2, systems that provide heated drinking water must be planned so as to minimise any risk of scalding. Specific temperatures are recommended for vulnerable user groups: in hospitals, schools or residential homes, the draw-off temperature must not exceed 43 °C. In shower facilities in nursery schools and special areas in nursing homes, the temperature should be limited to a maximum of 38 °C.

Even though these are normative recommendations from applicable standards, they can become definitive limits for operators in the context of public safety obligations. Operators must act to protect users from the dangers mentioned in the respective standard: either by implementing the proposed measures or by taking other action that reliably achieves the required level of safety.

Showers present a greater risk of injury from excessively hot water. A shower thermostat with anti-scalding protection should therefore always be a part of designing a safe and accessible shower facility. The SCHELL MODUS MD-T exposed shower fitting is equipped with ThermoProtect technology: this keeps the water temperature constant, even during pressure fluctuations in the system.

If the cold water line fails, the fitting stops the flow of water automatically to protect against scald injuries. A temperature lock is also provided: when activated, this ensures that the water temperature can only be set to a maximum of 38 °C in normal use – as recommended by DIN EN 806-2. The IsoBody technology also provides thermal insulation that keeps the fitting housing at more or less ambient temperature, which avoids any risk of burn injuries when touching the surface of the fitting.

SCHELL also offers a handy solution for adding anti-scalding protection as a quick and simple retrofit: the SCHELL angle valve thermostat. This minimises the risk of scald injuries by limiting the maximum outlet temperature. This temperature can be set as required – to the 43 °C specified by DIN EN 806-2, for example. Thanks to its practical form factor, the angle valve thermostat is also easy to retrofit even where installation space is tight.

Water management for hygienic operations

The SWS/SMART.SWS Water Management System from SCHELL is an especially smart choice for hygienically safe operations. The system helps operators to maintain drinking water quality and to ensure the regular exchange of water across all tapping points. Instead of handling this exchange of water manually, SCHELL electronic fittings with SWS/SMART.SWS can be networked for centralised management. Stagnation flushes can then be performed automatically in response to configurable time- or temperature-based controls. This supports the specified normal operation of the drinking water installation and helps to reduce risks to hygiene caused by stagnation.

SMART.SWS extends the water management system by adding remote functionality. Operators and facility managers can log on remotely to view and monitor key operating parameters such as stagnation flushes, temperature histories, water consumption and system messages for any building, and make immediate adjustments. Full documentation from the system can also be used as proof that measures to maintain drinking water quality have been completed.

Rules-based planning, safe operations

Achieving legally compliant drinking water installations requires the coordination of professional planning, suitable products, safe operations and an auditable set of system records. Accounting for risks early on creates a reliable basis for a hygienically safe drinking water installation that complies in full with regulations.