Return to Work Building Issues: Stagnant Water
Legionnaires, Heavy Metals Among the Hazards That Could Affect Your Building's Water System Safety As we all prepare to return to work, we may find addi...
Stagnant water in closed buildings becomes toxic within days. Legionnairesâ disease, lead contamination, and microbial biofilm develop silently while facilities are shuttered or operating at reduced occupancy. Turning the water system back on without flushing and testing exposes workers and occupants to serious respiratory and ingestion hazards.
⥠TL;DR: Stagnant water loses disinfectant residual, grows biofilm, and increases corrosion metals (lead, copper, iron). When system starts, aerosolized water can transmit Legionnairesâ disease. Facilities reopening after closure must flush the entire water system (potentially 1+ hour) and test for bacteria, heavy metals, and disinfectant residuals before occupancy. Testing against EPA Primary Drinking Water standards is essential.
Building water systems that have been sitting stagnant can have depleted disinfectant levels. This leads to increased bacteria and biofilm levels inside the system. It can also show increased levels of corrosion products such as iron, lead and copper depending on what your pipes are made from.
â ď¸ Why This Is a Workplace Hazard: Legionnairesâ disease is a serious lung infection spread by inhalation of contaminated water aerosols. A single case triggers OSHA investigation and recordkeeping requirements. Lead exposure in drinking waterâeven at levels below EPA action levelsâcreates chronic health risks. Facilities reopening without flushing and testing face liability if workers become ill.
Water System Safety: Environmental and Safety Hazards of Stagnant Water
As water sits unused in pipes, the disinfectant normally found in water (typically chlorine, but check with your water service to see what they are using) depletes to a point where a biofilm forms inside the pipe. This biofilm then grows and when the system is turned on water droplets can become airborne and inhaled causing many illnesses that can affect the lungs such as Legionnairesâ disease. Water that has sat in pipes also increases the amount of corrosion products from the piping itself and can lead to increased levels of metals in the water, depending on what your plumbing is made from. These increased levels can be ingested from various sources within a company such as drinking fountains, ice machines, plumbed coffee systems, water softeners, improperly maintained water heaters, on demand water heaters and dishwashers.
Water System Safety: Have a Plan to Deal With the Stagnant Water
Before buildings are reopened, a plan should be established to flush out the contaminates in your buildingâs entire water system. This flush should go all the way back to the main line from the municipality. You may need the assistance of a plumber or water engineer to properly determine the size and length of the pipes so the proper volume of the water system can be calculated. Once known, the volume will then determine the length of time the system will need to flow. In some cases, this could require over an hour of water flow. Be sure to pay special attention to any dead spaces in both the hot and cold-water systems. Remember, this water can be contaminated with bacteria that may cause respiratory issues and the hot water may be hot enough to cause burns so be sure to include proper safety equipment in the plan if doing large scale flushing.
Water System Safety: Clearance Testing
Once the system has been flushed, testing can be done on the water to determine if it meets the standards established by the Environmental Protection Agency (EPA) for Primary Drinking Water.
Frequently Asked Questions
Q: What hazards develop in building water systems after extended stagnation?
A: Stagnant water loses its disinfectant (usually chlorine) levels, allowing biofilm to form inside pipes. When the system is reactivated, airborne water droplets can transmit Legionnairesâ disease and other respiratory illnesses. Additionally, stagnant water increases corrosion products including lead, copper, and iron depending on pipe materials, creating ingestion hazards.
Q: How should a facility prepare its water system for reoccupancy?
A: Before reopening, a comprehensive flushing plan should be established that extends to the municipal main line. A water engineer or plumber should calculate the entire water system volume to determine the required flushing duration, which may exceed one hour. Special attention must be paid to dead spaces in both hot and cold-water systems, and appropriate safety equipment should be used due to bacterial contamination and hot water burn risks.
Q: What testing is required after flushing building water systems?
A: After flushing is complete, water testing should be conducted to verify the system meets EPA Primary Drinking Water standards. iSi Environmental can conduct clearance testing to confirm that bacteria levels, chemical contaminants, and disinfectant residuals meet EPA requirements before workers use the water system.
Q: Which facilities are most at risk from stagnant water hazards?
A: Any facility with extended closure or limited occupancy that has building water systems is at risk. This includes office buildings, manufacturing facilities, warehouses, and commercial spaces with plumbing systems including drinking fountains, ice machines, coffee systems, water softeners, dishwashers, and water heaters.
Q: What is the appropriate testing to verify water system safety after flushing?
A: After flushing, testing should evaluate: (1) Legionella species detection (culture), (2) bacterial coliform levels, (3) heavy metals (lead, copper, iron), (4) chlorine or appropriate disinfectant residuals, (5) pH, and (6) turbidity. Results must meet EPA Primary Drinking Water standards. Some states require additional monitoring for specific contaminants based on local water characteristics.
đ° Cost Comparison: Water system flushing and clearance testing costs $2,000â$8,000 depending on facility size and pipe complexity. Legionnairesâ disease outbreak in a facility can exceed $1 million in medical liability, workersâ compensation, and operational shutdown costs. Lead exposure claims can span years of health monitoring and remediation.
Need help with epa compliance? Contact iSi Environmental for a same-day quote, or explore our epa services to see how we can help your facility.
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