Cost
Cost per liter: made HOCl vs diluted household bleach
Diluted bleach at CDC’s household ratio and Eco One-made HOCl at 200 ppm, priced from dated online listings, with the math and its limits.
This page compares how the two hold their available chlorine over time. It is not a storage how-to. For containers, labels and re-testing, see How to store HOCl on disinfectant.org and HOCl storage and shelf life on hypochlorous.com.
The storage picture in one table
| HOCl | Bleach | |
|---|---|---|
| General trend | Chlorine loss is greater at lower pH. | Alkaline pH slows the loss. |
| In the studies | pH 5.0–6.4 products held chlorine for 21 days; pH 3.0 and below lost it rapidly (Takeda 2021). In closed storage, a weakly acidic electrolyzed solution kept its lab-test results for 5 weeks; in open storage, some of those results did not hold (Quan 2010). | 0.5% (5,000 ppm) dilutions in spray bottles kept stable FAC over 6 weeks; mean loss in the bottles not sprayed daily was 6% at week 5 and 7% at week 6 (Gow 2022). |
| What CDC reports | — | Tap-water dilutions above pH 8, in closed, opaque plastic containers at room temperature, can lose up to 40–50% of their free available chlorine in a month; sodium hypochlorite solution in a closed brown bottle did not decompose in 30 days (CDC 2008, p. 41). |
| Heat and light | Speed up loss (Kameda 2022). | Speed up loss (Kameda 2022). |
pH is the thread
Across electrolyzed solutions from pH 2.5 to 9.0, chlorine loss “decreased dramatically” as pH rose (Len 2002). Work on bleach itself points the same way from the other side: one study reports that shelf life “decreases exponentially below pH 8.5” (Sil 2025), and another found pH-adjusted bleach “less stable” than unadjusted bleach, with chlorate forming as it degraded (Frazer 2013).
So the storage gap is not about HOCl as such. Bring bleach down into the HOCl pH band and it starts to behave like an HOCl-type solution in storage too. Kept at pH 5.0–6.4, HOCl-type solutions held their chlorine for 21 days (Takeda 2021); in closed storage, a weakly acidic solution kept its lab-test results for 5 weeks (Quan 2010). Heat and light speed up the loss (Kameda 2022).
What that means for a comparison
In the studies cited here, storage stability favors bleach, mainly because it is kept alkaline. For bleach diluted at home, CDC’s household bleach page says: “Make a new diluted bleach solution daily.” Storage also bears on cost, since a solution that loses strength sooner is made more often. See Cost per liter for the dated figures and Same chlorine family, different pH for the pH background.
Sources: Len 2002 (PMID 11754569); Takeda 2021 (PMID 34152297); Quan 2010 (PMID 20004034); Gow 2022 (PMID 35109965); Sil 2025 (PMID 40021972); Frazer 2013 (PMID 23532317); Kameda 2022 (PMID 34690228); CDC 2008, p. 41; CDC household bleach page. Full entries on Sources.