Operator terms · Water
What is a clearwell?
A clearwell is a storage basin that holds treated water right after filtration and disinfection at a water plant. It gives disinfectant the contact time it needs to work and holds finished water ready to be pumped into the distribution system.
Last reviewed 2026-08-03
What it is for
After water is filtered and chlorine is added, it flows into the clearwell. The time the water spends there gives the disinfectant contact time to inactivate organisms before the water leaves the plant.
How it helps operations
The clearwell also acts as a buffer, holding a supply of finished water so the plant can run steadily while distribution demand rises and falls.
Common questions
- Where is a clearwell?
- At the water plant, after filtration and disinfection.
- Why does it matter?
- It provides disinfectant contact time and holds finished water.
- Is clearwell water treated?
- Yes; it holds finished, treated water ready for distribution.