Water Tank Cleaning in Lebanon: Frequency, Method, and Disinfection
AdvisorLB Team
Lebanese buildings store water in concrete ground tanks, polyethylene rooftop tanks, and stainless steel cisterns. Sediment, biofilm, and algae build up. WHO recommends cleaning at least once a year — more often if water is visibly cloudy or has odour.
How often
- Annual: minimum for any potable water tank.
- Every 6 months: tanks in warm South Lebanon or with intermittent supply.
- After contamination event: dead animal, sewage backflow, flood, repairs.
The proper method
- Empty the tank completely; isolate inlet/outlet.
- Remove sediment manually — buckets, brushes, vacuum.
- Scrub walls and floor with food-safe cleaner; rinse to drain.
- Inspect for cracks, rust (steel), or UV damage (polyethylene).
- Disinfect, rinse, and refill.
Safe disinfectants
- Sodium hypochlorite (chlorine bleach): 50–200 ppm for shock dose, contact 1 hour, then rinse and refill. Standard.
- Hydrogen peroxide: alternative for chlorine-sensitive systems.
- Avoid: household detergents, scented soaps, ammonia — never use them in drinking water tanks.
Choosing a cleaning service
- Ask if they use confined-space training for ground tanks.
- Should provide before/after photos and a written certificate.
- Confirm potable-grade chemicals and rinse procedure.
- Get a water test (free chlorine, turbidity) after refill.