The New EU Drinking Water Directive and Buildings: What Property Owners Need to Know About Water Temperatures


Introduction

In January 2021, the updated Drinking Water Directive (EU) 2020/2184 came into force. The directive sets higher standards for drinking water quality and introduces new obligations regarding risk management, materials in contact with drinking water, and monitoring.

For property owners – residential, multi-family, public, and commercial buildings – this means stricter requirements for how water installations are designed and operated. A particularly important aspect is the temperature of hot and cold water systems, as this directly affects both hygiene (Legionella risk) and energy efficiency.

This article covers:

  1. What the new directive requires.
  2. Temperature requirements and recommendations across the EU.
  3. How properties are affected in practice.
  4. Key measures property owners should implement.

What Does the New Drinking Water Directive (EU 2020/2184) Require?

  • risk-based approach to drinking water safety: buildings must conduct risk assessments covering the entire supply chain, from water intake to taps. Source: EU Commission
  • Stricter requirements for materials in contact with drinking water: pipes, fittings, and tanks must comply with EU “positive lists” to prevent harmful leaching.
  • Legionella monitoring: “priority premises” such as hospitals, swimming pools, hotels, and nursing homes must conduct Legionella risk assessments.
  • Action levels for Legionella are introduced – in many cases, values above 1,000 CFU/L require immediate corrective measures.

The directive does not specify exact water temperatures for all installations. Instead, it requires member states to set national requirements through building codes, public health laws, and water safety regulations.


Water Temperature and Legionella – Why It Matters

  • The 20–45 °C range is optimal for Legionella growth. Growth accelerates between 35–45 °C.
  • Above 50 °C, growth is inhibited. At 60 °C and higher, bacteria are quickly killed.
  • Below 20 °C, growth is very limited, but bacteria may remain dormant and reactivate if conditions change.

This means temperature control is one of the most powerful tools to prevent Legionella outbreaks in buildings. At the same time, operators must balance this with energy efficiency and scalding risks at taps and showers.


National Rules Across Europe

While the directive sets the framework, individual EU countries already have rules for building installations and Legionella prevention. Common requirements include:

  • Hot water at taps: must reach at least 50 °C.
  • Hot water storage tanks/boilers: must maintain at least 60 °C.
  • Hot water circulation systems (HWS/VVC): should not drop below 50 °C on the return loop.
  • Cold water supply: should remain below 20 °C, or max 24 °C after 8 hours of stagnation.
  • Risk assessments: mandatory in new builds and major renovations, and for priority buildings such as hospitals, hotels, and care homes.

Examples:

  • In Sweden, the Building Regulations (BBR) require hot water to be delivered at ≥50 °C at the tap, with boilers at ≥60 °C.
  • In Germany, DIN standards specify Legionella testing and temperature control for large-scale hot water systems.
  • In the UK, HSE guidance states hot water should reach 60 °C at storage and at least 50 °C within 1 minute at outlets.

How the Directive + Temperature Rules Affect Property Owners

1. Design and Installation

  • Systems must be sized and insulated to deliver safe temperatures.
  • Avoid “dead legs” where water stagnates.
  • Materials must comply with EU-approved positive lists.

2. Operation and Maintenance

  • Regular monitoring of water temperatures at tanks, circulation loops, and taps.
  • Flushing of unused outlets.
  • Documentation and corrective actions in case of Legionella risk.

3. Health and Safety

  • Property owners have a duty of care to prevent Legionella outbreaks.
  • Hospitals, care homes, and hotels are subject to stricter monitoring.

4. Energy Efficiency

  • High storage temperatures increase heat loss and energy consumption.
  • Balancing Legionella safety with energy performance is crucial.
  • Smart controls, insulation, and thermostatic mixing valves can reduce waste.
  • Failure to meet requirements may lead to fines, liability for illness, and reputational damage.
  • EU directives are binding – enforcement happens through national building regulations and health authorities.

Practical Temperature Guidelines for Buildings

Location / SystemMinimum/Recommended TemperaturePurpose
Hot water storage (boilers, tanks)≥ 60 °CKills Legionella and prevents growth.
Hot water at outlets (taps, showers)≥ 50 °CEnsures safe delivery temperature.
Hot water circulation return (HWS/VVC)≥ 50 °CPrevents stagnation and bacterial growth.
Cold water supply≤ 20 °C (≤24 °C after stagnation)Keeps water outside Legionella growth range.

Recommendations for European Property Owners

  1. Perform a Legionella risk assessment
    • Map out where water can stagnate or fall within the 20–45 °C range.
    • Include boilers, circulation loops, and seldom-used taps.
  2. Implement regular monitoring
    • Measure water temperatures at key points (storage, outlets, circulation).
    • Keep records for audits and compliance checks.
  3. Improve system design
    • Insulate both hot and cold water pipes.
    • Install thermostatic mixing valves near outlets to prevent scalding.
    • Eliminate unused pipe sections.
  4. Adopt operational routines
    • Flush taps and showers after long periods of disuse.
    • Clean and disinfect outlets like shower heads and hoses.
    • Conduct thermal disinfection (heat flushing) if contamination is suspected.
  5. Balance safety and energy efficiency
    • Maintain storage tanks at ≥60 °C but use mixing valves at outlets.
    • Optimize circulation systems to reduce unnecessary energy loss.
  6. Train staff and occupants
    • Ensure building managers understand Legionella risks.
    • Provide guidance to users in hospitals, hotels, or housing complexes.

Conclusion

The revised EU Drinking Water Directive (2020/2184) places stricter obligations on property owners to manage water hygiene risks. Water temperatures are central to this – both for preventing Legionella and for ensuring drinking water quality.

Across Europe, national building codes already require ≥60 °C in storage tanks≥50 °C at outlets, and ≤20 °C for cold water. Property owners must actively manage design, monitoring, and operation to comply with both EU law and national regulations.

While this demands investment and technical know-how, the result is safer buildings, reduced liability, and more sustainable water management.


Contact us at Tempivo if you need assistance in how to comply with these new rules in your properties.

Scroll to Top