Water stagnation and recommissioning after work or vacancy

Reduce risk from seldom-used branches, water heaters, shower heads and aerosol-producing devices after long shutdowns.

VERT / GREEN

Identify unused outlets and follow utility/manufacturer recommissioning guidance.

JAUNE / YELLOW

Stagnation, biofilm and some temperatures support Legionella growth; renovations can create dead or seldom-used branches.

ROUGE / RED

Complex system, vulnerable occupants, suspect water after long closure or major plumbing alteration: professional recommissioning plan.

Interactive triage

Helps choose the next step; it does not replace design, permits or professional diagnosis.

Outlet unused >2 weeks
Plan careful recommissioning following public-health guidance. Dead leg created by renovation
Correct the design rather than leaving stagnant piping. Unknown water-heater temperature
Verify setting and scald protection without improvising. Regular use and maintenance documented
Keep recommended maintenance/flushing schedule.

Useful tools and data

Branch map
Vacancy log
Water-heater settings

What the professional checks

Find dead legs/stagnation
Check temperatures/scald protection
Set recommissioning plan

Official sources

Checked 2026-08-22.

Santé Canada — Legionella

Related path

Continue with the right tools

These links connect this page to the next useful checks and decisions without repeating the full content.

Start from a symptomOrganize plausible causes, observations, urgency and the right professional.Open →Track water useCompare meter readings and flag unusual changes.Open →Review water resilienceConnect flooding, drainage and future events to building adaptations.Open →Score home resiliencePrioritize water, outages, fire, climate, health and records.Open →Plan site, drainage and utilitiesCoordinate access, water, sewer, wells, septic, grading and site constraints.Open →

V15

Remaining system checks not to miss

V15 covers issues that can block a project, cause a loss or become expensive once concealed.

Before closing wallsPost-renovation commissioningCodes + climate by province

V16

Advanced diagnostics to cross-check

V16 connects water, soil, climate, safety, materials and seasonal use to existing projects.

Drinking-water quality and treatment

V27

Project risks and overlooked interfaces

V27 connects payment, water, envelope, ventilation and jobsite details that often create costly surprises.

Laundry room leak containment

V28

Finish and service details to verify

V28 connects small details that become costly once finishes are closed.

Outdoor faucet: freeze and backflow protection