PREVENTION

Remove the Source of Contaminant

• Natural Processes
  • Inactivation of microorganisms on roofs and gutters that are free of composting vegetation through action of UV light, desiccation, and heat
• Active Processes
  • Reduce or remove vegetation around and above roofs to reduce organic matter decomposing on surfaces, materials entering tanks, nutrient loads for microorganisms, and sediment accumulation in tank bottom
  • Reduce or remove locations for animals and birds above roofs and gutters to reduce rooftop fecal loads
  • Remove or seal materials that could leach hazardous materials (especially lead, chromium, & arsenic) from roofs, gutters, and other system components

Keep organisms from colonization or growth

• Natural Processes
  • Rapid inactivation of new microorganisms entering tanks by fostering healthy biofilms in tanks
  • Competition for nutrients will help inactivate microorganisms
• Active Processes
  • Seal tanks from vectors, animals, sunlight, stormwater backflow, and surface or subsurface water entry
  • Exclude sunlight from tanks to prevent growth of algae and photosynthetic bacteria