Hypochlorous acid (HOCl) is a weak acid that forms when chlorine dissolves in water. It’s highly effective as a disinfectant and is naturally produced by white blood cells in humans and animals to fight off pathogens like bacteria, viruses, and fungi.
Key Facts About Hypochlorous Acid:
- Chemical formula: HOCl
- Appearance: Clear, colorless solution when diluted
- Natural occurrence: Produced by the immune system
- Uses:
- Disinfection: Used in hospitals, homes, and food processing
- Wound care: Safe for cleaning cuts and scrapes
- Water treatment: Used to sanitize drinking water, pools, and even wells
- Agriculture: Disinfects tools, surfaces, and sometimes produce
- Animal care: Used to clean animal housing and equipment
Benefits:
- Non-toxic and non-irritating in low concentrations
- Eco-friendly – breaks down into salt and water
- Broad-spectrum disinfectant – kills a wide range of microbes quickly
Safety:
Hypochlorous acid is generally safe when used properly, but concentration matters:
- Medical and commercial products are often in the 20–200 ppm range.
- At higher concentrations, it may become corrosive or irritating.
Hypochlorous Acid in Water Treatment & Well Shocking
What Is Well Shocking?
Well shocking (also called shock chlorination) is the process of disinfecting a well, typically in response to:
- Bacterial contamination (e.g., coliform or E. coli)
- Post-construction or repairs
- Flooding events
- Routine maintenance
The goal is to kill bacteria and biofilm within the well casing, plumbing system, and surrounding aquifer entry points.
Traditional Chlorine Methods
Historically, the most common method for shocking wells is with sodium hypochlorite (household bleach) or calcium hypochlorite (powdered chlorine). These are:
- Effective but harsh on plumbing systems.
- Highly alkaline, making pH balancing important.
- Corrosive to metals and rubber at high concentrations.
- Unpleasant to handle due to strong fumes and toxicity.
Why Consider Hypochlorous Acid?
Hypochlorous acid offers a softer, safer, and more effective alternative under certain conditions:
Benefits of HOCl in Well Shocking:
Fast-acting oxidizer
Kills bacteria, viruses, and fungi rapidly.
Effective at neutral pH
Works optimally around pH 5.5–7.5, closer to natural water pH.
Less corrosive
Gentler on pipes, seals, and components.
No harmful by-products
Breaks down into salt (NaCl) and water.
Low toxicity
Safer for handlers and surrounding environment.
Regulatory & Legal Considerations (Canada)
Alberta (and most provinces):
- Alberta Environment and Protected Areas (AEPA) does not currently recognize HOCl in its official well shocking protocols.
- Approved chemicals: household bleach (sodium hypochlorite, ~5.25–6%)
- The province requires:
- Calculation based on well depth and diameter
- Circulation of chlorinated water through entire system
- Post-treatment flushing and testing
