Household bleach is a solution of sodium hypochlorite. Hypochlorous acid (HOCl) is the main form of free chlorine in water near pH 5–6. Put both in water and you are dealing with one chemical system; what separates a jug of bleach from a batch of HOCl is mainly where the pH sits, and with it how strong the solution usually is, how long it holds, and how it should be handled.
This site sets those differences side by side as a reference. It does not score products or declare a winner. If you want a rated matchup, disinfectant.org keeps one: read HOCl vs bleach or open the rated compare table.
Side by side
| HOCl | Bleach | |
|---|---|---|
| What it is | Free chlorine held at low-to-neutral pH, so most of it is undissociated hypochlorous acid. | Sodium hypochlorite, kept alkaline, so most of it is hypochlorite ion (OCl⁻). |
| Usual pH | About 5–6.5 for slightly acidic electrolyzed solutions; about 6–7 for neutral ones. | Alkaline (above pH 8 for CDC's tap-water dilutions; 9.3 to above 11 in the cited studies). |
| Usual strength in use | Tens to a few hundred ppm of available chlorine in the studies cited here. | CDC-cited protocols run from about 100 to 5,000 ppm. |
| How long it holds | Depends heavily on pH. Solutions at pH 5.0–6.4 held their chlorine for 21 days, and a weakly acidic one kept its lab-test results for 5 weeks in closed storage; strongly acidic ones (pH 3.0 and below) lost chlorine fast. | Alkaline dilutions held well for weeks in some tests. CDC reports that tap-water dilutions above pH 8, kept in closed, opaque plastic containers, can lose up to 40–50% of their free available chlorine in a month. |
Each row is unpacked, with citations, on its own page. None of the rows is a rating.
Read by question
- Same chlorine family, different pH: the pH bands and which chlorine species dominates in each.
- Available chlorine: why equal-ppm lab tests and everyday use strengths answer different questions.
- Shelf life: what the storage studies found for each.
- Cost per liter: dated prices, with the arithmetic shown.
- Mixing: mixing hazards, and why acidified bleach in a lab paper is not a recipe.
- Odor: what the studies cannot yet tell you.
- Materials and corrosion: what happened to steel in the tests.
- Is hypochlorous acid the same as bleach?: the short terminology answer.
- The “100 times stronger” slogan: what the phrase leaves out.
- Sources and About this site.
Never mix HOCl solution with ammonia, bleach, strong acids or other cleaners; mixing with ammonia can release chloramine gas, and mixing with strong acids can release toxic chlorine gas. Never mix bleach with ammonia or with any acid or acid-containing product. If someone breathes in fumes or swallows either product, call Poison Help at 1-800-222-1222.
Making HOCl
Step-by-step instructions for a home batch are on hypochlorous.com: How to make hypochlorous acid at home. Comparing machines is covered in Choosing an HOCl generator.