Chlorate in Drinking Water
Complete contaminant profile for chlorate in drinking water, including sources, formation mechanisms, disinfection processes, health considerations, testing methods, treatment strategies, and drinking water safety guidance.
Quick Facts
What Is Chlorate?
Chlorate is an inorganic chemical byproduct that may form during the storage, handling, and use of chlorine-based disinfectants in drinking water treatment systems.
It is commonly associated with sodium hypochlorite, calcium hypochlorite, chlorine dioxide, and related disinfection technologies.
Why Chlorate Matters
Chlorate is not typically found in untreated source water. Instead, it develops as a result of disinfectant degradation and treatment-related chemical reactions.
How Chlorate Forms
Sodium Hypochlorite Aging
Liquid bleach solutions may gradually produce chlorate during storage.
Calcium Hypochlorite
Certain solid disinfectant products may contribute chlorate formation.
Chlorine Dioxide Systems
Chlorate may form as a secondary byproduct of chlorine dioxide treatment.
Storage Conditions
Temperature, sunlight, and storage duration influence chlorate production.
Health Considerations
Chlorate is monitored by drinking water authorities because of concerns associated with elevated exposure levels.
Modern water treatment facilities carefully manage disinfectant quality and treatment processes to minimize chlorate formation.
How Chlorate Is Detected
- Certified laboratory analysis.
- Utility compliance monitoring.
- Ion chromatography testing.
- Treatment plant process monitoring.
- Regulatory water quality programs.
Chlorate Control Strategies
| Control Method | Effectiveness | Comments |
|---|---|---|
| Fresh Disinfectant Supply | High | Reduces degradation-related formation |
| Temperature Control | High | Improves chemical stability |
| Optimized Storage Practices | High | Limits chlorate accumulation |
| Process Monitoring | High | Supports regulatory compliance |
| Treatment Optimization | Moderate to High | Reduces formation potential |
Chlorate and Water Utilities
Many water utilities routinely monitor disinfectant quality and storage conditions to reduce chlorate formation before treatment chemicals enter the water supply.
Good operational practices play a major role in controlling chlorate concentrations.
Chlorate vs Chlorite
- Both are inorganic disinfection byproducts.
- Both require laboratory testing for accurate measurement.
- Chlorite is strongly associated with chlorine dioxide treatment.
- Chlorate is often associated with disinfectant degradation and storage.
- Both are managed through treatment optimization.
Related Contaminants
Frequently Asked Questions
What is chlorate?
Chlorate is an inorganic byproduct that may form when chlorine-based disinfectants degrade during storage and treatment.
Is chlorate naturally present in water?
Generally no. It is primarily associated with drinking water treatment processes.
How is chlorate controlled?
Through proper disinfectant storage, process monitoring, and treatment optimization.
What is the difference between chlorate and chlorite?
Both are disinfection byproducts, but they are formed through different treatment pathways.
Can chlorate be detected by taste or smell?
No. Laboratory analysis is required.
Quick Summary
Chlorate is an inorganic disinfection byproduct associated with chlorine-based disinfectants and treatment system operations. It forms primarily through disinfectant degradation and storage-related processes. Water utilities manage chlorate through proper chemical handling, storage practices, process monitoring, and treatment optimization to maintain drinking water safety.