Job Safety Analysis: Wet Well Cleaning

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Step Potential Hazard Control
Assess work area Traffic exposure, uneven ground, slip hazards Conduct site walk; set up MUTCD compliant traffic control; identify stable work zone
Inspect PPE, tools, and equipment Defective gas monitor, damaged blower, worn hoses Calibrate gas monitor; inspect blower, hoses, and retrieval system; replace defective equipment
Don required PPE Exposure to sewage, aerosols, sharp debris Wear gloves, face shield, protective clothing, and respirator if needed
Test atmospheric conditions Hydrogen sulfide, methane, low oxygen Test at top, middle, and bottom; do not proceed until readings are safe; monitor continuously
Ventilate wet well Toxic gases, oxygen deficiency Use blower with ducting; ventilate throughout operation; confirm airflow reaches bottom
Lockout tagout pump power Unexpected pump start, electrical shock Shut down pumps and panel; apply lockout tagout; verify no power before cleaning
Open wet well hatch Fall hazard, dropped objects Lift with proper tools; secure hatch open; install temporary barriers around opening
Set up tripod and retrieval system (if entry required) Fall hazards, winch failure Position tripod securely; attach winch to harness; test retrieval system
Perform cleaning from the surface when possible Aerosol generation, splash hazards Use vactor suction or jetting wand from above; keep face shield and respirator in place
Remove debris and sediment Sharp objects, splash contact, biological hazards Use long handled tools; avoid leaning into opening; stage debris in sealed containers
Monitor gas levels during agitation Sudden release of gases from sludge Continue atmospheric monitoring; evacuate area if alarms activate
Enter wet well only if absolutely necessary Confined space hazards, fall risk Follow full confined space entry procedures; maintain attendant and communication
Continue cleaning and inspection Slips, entrapment, aerosolized waste Keep footing secure; use lighting; avoid unsupported stepping areas
Exit wet well safely Ladder slip, fatigue Climb slowly; maintain three points of contact; avoid snagging harness
Close wet well and secure hatch Pinch points, dropped lid Lower carefully; ensure latch is fully engaged
Decontaminate tools and PPE Biological contamination, chemical exposure Rinse tools and boots; bag disposable PPE; wash hands thoroughly
Final site cleanup Residual contamination, trip hazards Remove debris, spills, and equipment; ensure site is clear
Restore power and test pumps Sudden startup, water surge Stand clear during activation; verify pumps operate correctly
Remove traffic control Exposure to traffic Remove signs and cones in reverse order; maintain lookout; keep PPE on until clear

Suggested Personal Protective Equipment

  • Hard hat

  • Safety glasses or face shield

  • High visibility vest or jacket

  • Steel toe boots

  • Waterproof boots or chest waders

  • Chemical resistant gloves (nitrile or neoprene)

  • Long pants and long sleeves

  • Respirator when sewer gases or aerosols are present

  • Full body harness with lifeline (for any entry)

  • Disposable coveralls for heavy contamination

Always have a complete, well-stocked first aid kit available.

JSA Category: Water and Sewer Department Operations

* The steps, hazards, and controls displayed above may be incomplete or not suit your department's needs. All job safety analyses should be a completed with frontline worker input to ensure that each potential hazard is identified and mitigated.

Please read about The Essentials Elements of a Solid Job Safety Anaylsis here.

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Job Safety Analysis
Department: __________________________________
Job/Task:   Wet Well Cleaning
Location: __________________________________
Date: ____ /____ /____
Supervisor: __________________________________
Crew: __________________________________
Step Potential Hazard Control
Assess work area Traffic exposure, uneven ground, slip hazards Conduct site walk; set up MUTCD compliant traffic control; identify stable work zone
Inspect PPE, tools, and equipment Defective gas monitor, damaged blower, worn hoses Calibrate gas monitor; inspect blower, hoses, and retrieval system; replace defective equipment
Don required PPE Exposure to sewage, aerosols, sharp debris Wear gloves, face shield, protective clothing, and respirator if needed
Test atmospheric conditions Hydrogen sulfide, methane, low oxygen Test at top, middle, and bottom; do not proceed until readings are safe; monitor continuously
Ventilate wet well Toxic gases, oxygen deficiency Use blower with ducting; ventilate throughout operation; confirm airflow reaches bottom
Lockout tagout pump power Unexpected pump start, electrical shock Shut down pumps and panel; apply lockout tagout; verify no power before cleaning
Open wet well hatch Fall hazard, dropped objects Lift with proper tools; secure hatch open; install temporary barriers around opening
Set up tripod and retrieval system (if entry required) Fall hazards, winch failure Position tripod securely; attach winch to harness; test retrieval system
Perform cleaning from the surface when possible Aerosol generation, splash hazards Use vactor suction or jetting wand from above; keep face shield and respirator in place
Remove debris and sediment Sharp objects, splash contact, biological hazards Use long handled tools; avoid leaning into opening; stage debris in sealed containers
Monitor gas levels during agitation Sudden release of gases from sludge Continue atmospheric monitoring; evacuate area if alarms activate
Enter wet well only if absolutely necessary Confined space hazards, fall risk Follow full confined space entry procedures; maintain attendant and communication
Continue cleaning and inspection Slips, entrapment, aerosolized waste Keep footing secure; use lighting; avoid unsupported stepping areas
Exit wet well safely Ladder slip, fatigue Climb slowly; maintain three points of contact; avoid snagging harness
Close wet well and secure hatch Pinch points, dropped lid Lower carefully; ensure latch is fully engaged
Decontaminate tools and PPE Biological contamination, chemical exposure Rinse tools and boots; bag disposable PPE; wash hands thoroughly
Final site cleanup Residual contamination, trip hazards Remove debris, spills, and equipment; ensure site is clear
Restore power and test pumps Sudden startup, water surge Stand clear during activation; verify pumps operate correctly
Remove traffic control Exposure to traffic Remove signs and cones in reverse order; maintain lookout; keep PPE on until clear
Suggested Personal Protective Equipment


Supervisor signature: __________________________________
Employee initials: ______________________________________________________________________________________________________