Legionella risk assessment

1–5 methodology

Score likelihood and consequence from 1 to 5. The matrix is an AquaNordic prioritisation method; regulatory rules remain separately versioned.

LikelihoodConsequence

Risk matrix

1×1

1×2

1×3

1×4

1×5

2×1

2×2

2×3

2×4

2×5

3×1

3×2

3×3

3×4

3×5

4×1

4×2

4×3

4×4

4×5

5×1

5×2

5×3

5×4

5×5

Assessment sections

System design · vulnerable users · temperatures · stagnation · dead legs · outlets · storage · maintenance · flushing · sampling · laboratory results · corrective actions · evidence/photos