Drinking water hygiene has been an increasing focus for several years. With the new SVGW guideline, the requirements are now specified. Not everyone enjoys it.
The "Guideline for hygiene in drinking water installations (W3/E3)" of the Swiss Association for Gas and Water (SVGW) came into force on September 1st. The document describes the necessary measures to ensure perfect drinking water quality according to the rules of technology. The focus is not on the public water supply, but on the hot and cold drinking water installation in buildings.
With this, the W3/E3 makes building operators and owners more clearly responsible. The formulation of concrete measures is not surprising, as there have been signs of stricter regulation of drinking water hygiene for years. The revised Foodstuffs Act (LMG) has been in force since May 1, 2017. In the course of the revision, the Foodstuffs Ordinance (LGV) and the new Drinking, Showering and Bathing Water Ordinance (TBDV) were also put into effect.
Legal finesse
The requirements for bath and shower water only apply to publicly accessible buildings, private ones are exempt from this. And anyone who only obtains drinking water for personal consumption is not subject to the TBDV. However, as soon as he sells water to third parties, he must comply with the provisions of the TBDV. Cosimo Sandre, Technical Advisor Water at the SVGW, says: "In the 'last mile', the owner or operator must take suitable measures to ensure the perfect drinking water quality up to the point of withdrawal."
In this sense, the ordinance not only affects the owners of hotels, hospitals, retirement and care centers, school and sports facilities, etc., but also those who rent one or more apartments to third parties. According to Sandre, it makes sense that not only the public water supply, but also private owners and operators should be held more accountable: “Billions of francs are spent in Switzerland on the extraction, treatment, storage and distribution of clean drinking water. Responsibility for drinking water quality normally passes from the municipal water supply to the owner or operator of the building's drinking water installation at the main water meter.»
With the new W3/E3, these obligations are now formulated more specifically. For example, the exact specifications for hot drinking water installation: The temperature at the outlet of the hot water tank or flow water heater must be at least 60 degrees Celsius. The minimum temperature for lines that are kept warm is 55 degrees Celsius, and 50 degrees Celsius for the tapping points. In addition, the W3/E3 also includes numerous other topics, such as the following points:
- Selection of suitable materials for the drinking water installation
- Handling of material, hygiene on the construction site
- Correct commissioning and handover of the drinking water installation
- Requirements for temporary drinking water installations inside or outside buildings
- Basics for self-control
The increased attention to private drinking water installations is due to new studies and findings, particularly with regard to the legionella problem. Although the discourse on health and disease in 2020 is clearly dominated by the coronavirus, legionella remains a serious problem. Last year, the Federal Office of Public Health (BAG) registered almost 600 cases of Legionnaires' disease in Switzerland. Compared to 2016, this corresponds to an increase in cases of around 60 percent. Experts also assume a high number of unreported cases.
For this reason, legionella research has been intensified in Switzerland and Europe in recent years. As a result, knowledge has grown significantly, and not always to the delight of those involved. Various research projects, as well as practical cases, have shown that legionella can establish and/or multiply not only in hot water, but in the worst case also in cold water.
Attention has also been drawn to the so-called VBNC state (“viable, but non-culturable”). Legionella can no longer multiply at temperatures between 48 and 55 degrees Celsius, but they may still be viable and infectious. In other words: If legionella no longer multiply in an installation, this does not mean that all of them are dead.
Little enthusiasm
So it is actually clear that drinking water installations in buildings need to receive more attention. But how much self-control is enough, and how much regulation is needed? There is opposition from the Swiss homeowners' association. Thomas Ammann, head of the energy and construction technology department at HEV Switzerland, cites three reasons for this: authority to issue directives, practicability and deadlines. "It is not clear to us why the SVGW can issue regulations for owners and tenants," says Ammann, "because half of the members of the SVGW are water supply companies, cantonal specialist agencies, specialist planners and probably also a few plumbers. The SVGW should create its set of rules for these professional groups.»
In contrast to the recommendations of the federal offices, which are largely written with optional formulations, the SVGW adopts a mandatory tone in the W3/E3. “This puts the association above the legislature. It's not acceptable to us in this form," says Ammann.
practical?
In addition, HEV Switzerland criticizes individual requirements that are “not practicable”, says Ammann: “If individual tenants go on vacation, you cannot simply block off entire floor distributions. Neither can the landlord force the tenant to hire someone to run the water regularly during vacations or longer absences.” Thirdly, from the point of view of HEV Switzerland, the maximum period for the first filling before moving into the building (72-hour rule) is "excessive, especially for larger buildings".
The homeowners are well aware of their responsibility for drinking water installations, says Ammann: "They regularly carry out maintenance work, for example having filters checked or boilers decalcified." As the owner, however, one must be able to rely on “that this work is carried out using the current state of the art”. A leaflet with tips and information on maintaining the drinking water infrastructure is therefore "much more useful than comprehensive regulations".
A "work in progress"
Naturally, the SVGW takes a different perspective. Technical rules drawn up by industry associations are instructions for action that show a way to comply with a law, a regulation or a technical fact. For this reason, the TBDV does not describe in detail how a building drinking water installation is to be built or operated, but refers to the generally recognized rules of technology.
So it's not about harassment, says Cosimo Sandre: "With a holistic view, the W3/E3 directive wants to put drinking water, our most important food, in the foreground and define clear requirements for industry and the sanitary sector." For example, a critical discussion should be held about the number and location of cold and hot water tapping points in order to avoid stagnation. Cold water should also remain as cold as possible, which is why in future installation shafts should be thermally separated from cold and hot water.
The discussion about the new guideline will also focus on formulating the distinction between new construction and existing buildings more clearly. “The measures described in the guideline serve to improve drinking water hygiene and good practice as part of the legally prescribed self-monitoring of the owner or operator and if the maximum legionella values are exceeded,” says Cosimo Sandre. In the case of conversions, extensions and refurbishments of existing systems, the requirements must be complied with within the scope of the technical possibilities.
