London is currently investigating a cluster of Legionnaires’ disease cases across the north‑west and south‑west of the city.  As of 23 March 2026: 

  • 8 confirmed cases 
  • Further cases under investigation 
  • No confirmed source yet, with UKHSA leading the response [gov.uk] 

 

The wider risk remains low, but it highlights a key point. 

 The Shift  

Across Europe, Legionella control is tightening: 

  • Stricter limits in healthcare settings 
  • Greater focus on materials and system design 
  • Clearer intervention thresholds 

 

The focus is no longer just water quality at source, it’s what happens inside the building.

 

Where Risk Builds 

Legionella grows in: 

  • Hot water systems 
  • Dead legs 
  • Low-use outlets 

 

That’s where control measures now sit. 

Hygiene flush, built into the switch. A programmable piezo sanitary switch with autonomous 24, 48 or 72 hour hygiene flush cycles. IP69K sealed. Built for institutional facilities now under tighter Legionella protocols across the UK and Europe.

The Reality  

Compliance still relies heavily on: 

  • Manual flushing 
  • Routine walk‑throughs 
  • Logged maintenance cycles

 

On large estates, that’s a significant ongoing burden. 

A Smarter Approach 

 The PTF-22-PDC is a programmable piezo switch for automated hygiene flushing.
Using solid-state (non-mechanical) piezo technology, it’s designed for high reliability in wet environments. 

It connects to a solenoid valve and: 

  • Automatically runs outlets at set intervals to prevent stagnation 
  • Reduces manual flushing requirements 

 

Key features: 

  • 24 / 48 / 72-hour flush cycles 
  • Battery or mains powered 
  • Compatible with latching and non‑latching valves 
  • No moving parts, improved durability 
  • IP69K sealed for washdown environments 

 

Helping reduce workload while supporting consistent compliance.  No missed flushes. Piezo-driven control for Legionella risk where it actually occurs. 

Bottom line:   

Legionella risk is local to building systems and smart, automated control at the outlet level is becoming part of the solution.