LEGIONELLA COMPLIANCE

Key steps

1. 1Identify all water systems in scope (hot, cold, cooling circuits, decorative water features)
2. 2Map the water distribution network: storage tanks, calorifiers, recirculation loops, dead legs
3. 3Assign a risk score to each installation based on water temperature, usage frequency and user vulnerability
4. 4Define monitoring points and minimum sampling frequencies per Italian guidelines
5. 5Draft the written risk assessment document with corrective-action plan and review date

Key steps

1. 1Verify hot-water storage temperature ≥ 60 °C at the calorifier outlet
2. 2Confirm recirculation return temperature ≥ 50 °C at the furthest point
3. 3Check that all shower heads and taps are flushed or replaced after seasonal closure
4. 4Confirm cooling tower chemical treatment log is up to date
5. 5Ensure accredited sampling report is less than 6 months old (12 months for low-risk installations)

Key steps

1. 1Start from the water entry point (mains connection or storage tank) and trace the full distribution network
2. 2Identify high-risk outlets: showers used infrequently, dead-leg branches, outlets distant from the calorifier
3. 3Select at minimum: calorifier outlet, recirculation return, 2–3 cold-water storage samples and 5–8 representative distal outlets
4. 4Specify first-draw or post-flush sampling for each point (risk-based)
5. 5Document the sampling map in the Water Safety Plan with GPS or floor-plan coordinates

Key steps

1. 1Step 1 (0–2 hours): Receive and verify results — confirm exceedance level and affected outlets
2. 2Step 2 (2–8 hours): Restrict use of affected outlets; notify senior management and health & safety officer
3. 3Step 3 (8–24 hours): Select disinfection method based on contamination level and system type (thermal shock, hyperchlorination or copper-silver ionisation)
4. 4Step 4 (24–48 hours for healthcare): Notify local health authority (ASL/ASP) if required by law
5. 5Step 5 (post-disinfection): Carry out accredited post-treatment sampling; do not reopen affected outlets until results confirm compliance

Key steps

1. 1Set hot-water storage (calorifier) temperature to a minimum of 60 °C — ideally 65 °C to provide adequate buffering
2. 2Ensure recirculation return temperature does not fall below 50 °C at any measurement point
3. 3Insulate all hot-water pipes to maintain temperature and prevent heat loss in cold sections
4. 4Store cold water below 20 °C; insulate cold pipes from heat sources
5. 5Install digital temperature loggers at key points to create an audit trail and detect drift early

Key steps

1. 1Section 1 — System description: facility type, water entry, network schematic, calorifier capacity and age
2. 2Section 2 — Risk assessment summary: risk score per installation, priority points and action triggers
3. 3Section 3 — Sampling calendar: point-by-point schedule for the next 12 months with method (culture/qPCR) and responsible party
4. 4Section 4 — Action threshold matrix: by contamination level and facility type (consistent with State-Regions Agreement 2015 Annex 3)
5. 5Section 5 — Corrective-action flowchart: decision tree linking each threshold to a specific response protocol
6. 6Section 6 — Documentation and records: who stores results, for how long (minimum 5 years) and in what format
7. 7Annual review: update risk assessment, revise sampling plan based on previous 12 months' results

Key steps

1. 1Thermal shock: raise calorifier to ≥ 70 °C for 30 min; flush all outlets sequentially to 60 °C for 5 min; requires scalding precautions and temporary outlet closure
2. 2Hyperchlorination: dose free chlorine to 20–50 mg/L; hold for 1–2 hours; flush to residual ≤ 0.5 mg/L before reopening; corrosion risk on some pipe materials
3. 3Copper-silver ionisation: continuous electrochemical dosing (Cu 0.2–0.4 mg/L, Ag 0.02–0.04 mg/L); most effective long-term biofilm control; requires monthly maintenance of electrode units
4. 4UV treatment: effective for planktonic cells in recirculating systems; no residual effect in dead legs or storage tanks; typically used in combination with chemical treatment
5. 5Post-treatment: regardless of method, post-disinfection accredited culture sampling is mandatory before restoring normal operation

Key steps

1. 1Risk assessment: classify cooling tower as high-risk installation; complete biological risk assessment before commissioning
2. 2Chemical treatment programme: biocide rotation, corrosion and scale inhibitor dosing, pH and conductivity control (weekly measurements)
3. 3Blowdown management: maintain cycles of concentration within design limits to prevent mineral build-up
4. 4Drift eliminator inspection: check for damage, blockage or bypass monthly; replace if efficiency is compromised
5. 5Biological monitoring: Legionella culture twice per year minimum; add Total Viable Count (TVC) at 22 °C and 37 °C monthly
6. 6Annual inspection: drain, clean, descale, inspect all internal surfaces; replace worn components before recommissioning
7. 7Shutdown and recommissioning: disinfect before extended shutdown and before start-up; confirm with post-treatment Legionella sampling

Key steps

1. 1Verify ACCREDIA accreditation: check the laboratory on the ACCREDIA online register (accredia.it); confirm that UNI EN ISO 11731 is listed in the accreditation scope
2. 2Check method coverage: the laboratory must analyse both L. pneumophila and total Legionella spp.; serogroup determination should be available on request
3. 3Confirm turnaround time: 7–10 working days is standard for culture; verify whether expedited qPCR is offered
4. 4Assess logistical capability: the laboratory must provide chain-of-custody bottles, transport packaging and collection coordination in your region
5. 5Review report format: the signed accredited report must include CFU/L per point, applicable thresholds, uncertainty of measurement and the laboratory's ACCREDIA accreditation number