The water treatment process
The water treatment process consists of five steps:
- Coagulation/flocculation - Raw water from terminal reservoirs is drawn into mixing basins at our treatment plants where we add alum, polymer and sometimes lime and carbon dioxide. This process causes small particles to stick to one another, forming larger particles.
- Sedimentation - Over time, the now-larger particles become heavy enough to settle to the bottom of a basin from which sediment is removed.
- Filtration - The water is then filtered through layers of fine, granulated materials — either sand, or sand and coal, depending on the treatment plant. As smaller, suspended particles are removed, turbidity diminishes and clear water emerges.
- Disinfection - To protect against any bacteria, viruses and other microbes that might remain, disinfectant is added before the water flows into underground reservoirs throughout the distribution system and into your home or business. We carefully monitor the amount of disinfectant added to maintain quality of the water at the farthest reaches of the system. Fluoride occurs naturally in our water but also is added to treated water.
- Corrosion control - pH is maintained by adding alkaline substances to reduce corrosion in the distribution system and the plumbing in your home or business.