Drinking Water Supply: Systems, Planning and Infrastructure __

According to the WHO and UNICEF, more than two billion people have no access to a safely managed drinking water supply. However, even in regions outside these hotspots, demands are rising: ageing networks, climate change, water stress, new pollutants, higher hygiene standards and more complex buildings are changing the conditions under which drinking water is supplied and distributed.

This brings into focus an infrastructure that usually remains invisible in everyday life. The drinking water supply comprises a technical system consisting of the water source, treatment, storage, the public network, building installations and ongoing operations. Between the waterworks and the point of use, planning, pressure maintenance, material selection, pipework routing and maintainability determine whether drinking water remains permanently available – in sufficient quantities, of suitable quality and under stable hydraulic conditions.

How does the water supply work, from raw water to the building?

To ensure a reliable water supply, the entire process chain must work together seamlessly. It all starts with raw water. This can be sourced from groundwater, springs, reservoirs, rivers, lakes or bank seepage. Depending on its source and quality, this water is transported to the water treatment works, where it is treated to produce drinking water.

Typical processes include filtration, iron removal, manganese removal, deacidification, disinfection and other treatment steps. Which processes are required depends on the raw water. Groundwater presents different technical requirements to surface water. Bank filtrate, in turn, differs from spring water or water from reservoirs.

After treatment, drinking water is stored and distributed via public networks. Storage tanks, pumping stations, pressure zones and pipe networks ensure that water is available in sufficient quantities and at the appropriate pressure. Key parameters at the point of connection to the building’s plumbing system include water hardness, pH value, temperature, pressure, dissolved substances and disinfection methods.

Centralised and decentralised drinking water supply: an overview of supply models

The supply structure influences every project. It determines which responsibilities lie with the supplier, what technical systems are required in the building, and which risks need to be taken into account at an early stage.

In Germany and large parts of Europe, public drinking water supply via centralised systems predominates. Waterworks, local authorities, special-purpose associations or water supply companies operate networks, storage facilities and pumping stations. This usually provides clear baseline data for planning: water analysis, property connections, pressure conditions and technical connection requirements.

Decentralised drinking water supply is something of an exception in Germany. Internationally, however, it is much more common, for example in rural areas, on islands, at tourist resorts or in regions with less developed public infrastructure.

An additional challenge is intermittent water supply. According to the International Water Association, at least 1.3 billion people worldwide are affected by intermittent water supply – systems in which pipes are not continuously pressurised. If pipes are regularly drained and then refilled, this gives rise to risks of contamination, deterioration in water quality and potential health risks.

Public drinking water supply and building installations: planning interfaces correctly

The public drinking water supply ends at a defined handover point. In Germany, the DVGW defines the main shut-off valve as the boundary at which the water supplier’s responsibility ends. From this point onwards, responsibility for the drinking water installation within the building begins.

This interface requires particular attention during the planning stage. It links public infrastructure with the building’s internal systems. Factors such as mains pressure, water meters, filters, safety valves, pressure-reducing valves and pressure-boosting systems are relevant here. The building’s subsequent operating conditions also depend on these.

For the design and installation of building services, the actual pressure conditions at the building connection, the minimum flow pressure during peak demand and the water analysis provided by the water supplier are important. Equally important are the location and accessibility of the plant room, as well as the sizing of main pipes, risers and distribution manifolds.

Legislation and regulations governing drinking water supply

In Germany, the Drinking Water Ordinance sets out the requirements for water intended for human consumption. The protection of the public drinking water supply network is also crucial for planning purposes. Depending on the installation and the risk involved, a suitable backflow preventer or other safety device must be provided.

Further requirements may apply at international level. One example is the regulation of PFAS in the USA. In 2024, the EPA set legally binding limit values for several PFAS compounds in drinking water for the first time. For large properties or sensitive uses, this may result in additional coordination and planning requirements, for example if supplementary treatment steps such as activated carbon filtration, ion exchange or reverse osmosis are planned at the point of entry. Such post-treatment processes affect pressure loss, maintenance requirements and space requirements in the plant room.

Pipe network, pressure maintenance and pipework systems: technical planning of the distribution system

Beyond the handover point, the building’s internal pipework network takes over distribution. In small buildings, this task seems straightforward. In hospitals, hotels, schools, industrial estates, high-rise buildings or public buildings, however, it quickly becomes complex. In such cases, pressure zones, flow paths, risers, circulation, storage tanks and fittings determine whether the drinking water supply functions reliably.

In this context, security of supply means more than just adequate water quality. It encompasses hydraulic stability, sufficient pressure, appropriate flow rates and operation that prevents stagnation. Well-founded pipework design is therefore crucial to achieving the right balance. Pipes that are too small lead to pressure losses, noise and restricted use. Pipes that are too large can result in low flow velocities and longer residence times.

Several questions are therefore central to technical design:

• What are the actual pressure conditions at the transfer point?
• What flow rates are required under typical and peak usage conditions?
• Where are there long flow paths, rarely used areas or potential stagnation zones?
• What temperature control is realistically achievable for cold and hot water?
• Which components must remain accessible for maintenance, flushing or future replacement?

These questions determine whether the system will operate reliably in day-to-day use, whether maintenance can be carried out without unnecessary intervention, and whether future changes in usage can be managed from a technical perspective.

The operator’s perspective must also be taken into account in this planning. Pipes, shut-off valves, distribution units and fittings must remain accessible. Particularly in large buildings, a poorly documented or hard-to-reach installation can result in high follow-up costs.

Piping systems for a reliable drinking water supply

Piping systems play a central role in the drinking water supply: they distribute cold and hot water from the transfer point to the taps and must be permanently adapted to water quality, pressure levels, temperature control and the building’s structure.

The choice of material is directly linked to the quality of the water. In the case of metallic pipework systems, parameters such as pH, hardness, salinity, oxygen content, temperature and disinfection methods can influence corrosion behaviour, deposits and long-term operational reliability. Therefore, the choice of material in drinking water supply systems is always dependant on the specific operating conditions.

PP-R plastic pipework systems offer a corrosion-resistant alternative. aquatherm green has been developed for drinking water installations and is designed for the distribution of cold and hot water. The system is available in various sizes and pressure ratings and can be integrated into a range of building structures – from the plant room, through main and riser pipes, to distribution at the user level.

Joining technology is also part of this system-based approach. With the PP welding processes, the pipe and fitting are joined with a material-to-material bond. The result is a homogeneous joint made from the same material. This ensures a permanently leak-proof connection and a seamless pipework system design.

Resilient drinking water supply: planning infrastructure to meet new requirements

The demands placed on drinking water systems are changing. Droughts, heavy rainfall, ageing networks, regional water shortages and rising investment requirements are increasing the pressure on infrastructure and building design. In this context, resilience means designing systems in such a way that they operate safely under realistic operating conditions, remain maintainable and can be adapted to changing requirements.

In international projects, further factors come into play:

• Higher ambient temperatures and different chemical compositions of water
• Different disinfection methods and fluctuating network pressures
• Supply via storage tanks, pumping systems or local treatment processes

Even within the building itself, resilience remains closely linked to hygiene. Stagnation, poor temperature control or poorly insulated pipes can compromise drinking water hygiene. Issues such as Legionella in drinking water are linked to hot water production, circulation, insulation, flow paths, usage patterns and maintenance.

Conclusion: Plan drinking water supply holistically

The WHO recommends a risk-based approach to the entire supply chain: from the water source through water treatment works, storage facilities, public networks and domestic connections to distribution within buildings. This approach is logical, as hazards do not only arise at the end of the chain. Water Safety Plans (an approach recommended by the WHO for risk management in drinking water supply) therefore assess all stages of the supply chain and implement control measures where risks may arise. In short, drinking water supply is a systemic challenge.

For professional projects, this means that water quality, pressure conditions, usage, building size, material requirements and operation should be considered holistically from the outset. After all, it is only through seamless coordination that the drinking water supply can remain reliably secure, hydraulically stable and maintainable in the long term.

In smaller buildings, these interrelationships often remain manageable. In large properties, industrial sites, hotels, hospitals and educational establishments, however, strategic planning is required.

aquatherm supports you in the planning and implementation of suitable pipework systems for drinking water installations – from technical design through to project-specific system solutions.