Water — Skill
Bleach is in almost every home, costs nothing, and can disinfect water from almost any source. The protocol takes less than a minute to learn. Most people who think they know it are using the wrong bleach or the wrong dose.
Step zero
The EPA is specific: use regular, unscented household bleach with 6–8.25% sodium hypochlorite as the only active ingredient.[1] That eliminates the majority of bleach products currently on most grocery store shelves.
Scented bleach contains fragrance chemicals not approved for water treatment. Splashless bleach has a thickened formula that doesn't disperse properly. Color-safe bleach uses hydrogen peroxide, not sodium hypochlorite — it won't disinfect. Bleach with added cleaners, surfactants, or soaps introduces chemicals into drinking water.
Check the label before relying on any bleach for water treatment. The only active ingredient should be sodium hypochlorite at 6–8.25%. Clorox Regular Bleach (the standard blue bottle) meets this specification. Store brands meeting the same spec are equivalent.
Bleach types — use vs. avoid
Regular unscented bleach (6–8.25% NaOCl)
The only type appropriate for water disinfection. Check the label for concentration and single active ingredient.
Scented bleach
Contains fragrance chemicals. Not approved for water treatment.
Splashless / ultra-concentrated formulas
Thickened or ultra-concentrated formulas don't disperse or dose predictably for water treatment.
Color-safe bleach
Uses hydrogen peroxide, not sodium hypochlorite. Will not disinfect water.
Bleach with added cleaners or surfactants
Introduces cleaning chemicals into drinking water. Not appropriate for water treatment.
Bleach shelf life
Household bleach loses roughly 20% of its disinfecting strength per year from manufacture date.[2] A two-year-old bottle may have only 60% of its original concentration. Buy fresh bleach annually for reliable emergency treatment. Write the purchase date on the bottle. Store in a cool, dark location — heat accelerates degradation.
The protocol
The EPA protocol for disinfecting water with household bleach.[1] Do not skip steps — each one matters.
Clear water
drops per gallon
(approximately 1/8 teaspoon)
Cloudy water
drops per gallon
(approximately 1/4 teaspoon)
If the water is cloudy, discolored, or has visible sediment, filter it first. Pour through a clean cloth, paper towel, or coffee filter to remove as much turbidity as possible. Organic matter and sediment consume chlorine before it can disinfect — pre-filtering significantly improves treatment effectiveness.
Clear water: skip to Step 2. Cloudy water that can't be pre-filtered: use the doubled dose (16 drops/gallon) and accept that effectiveness may be reduced.
Use a medicine dropper or a syringe to measure drops accurately. Standard household bleach droppers dispense approximately 1/16 teaspoon per 8 drops — check yours by counting a known volume. Add the correct number of drops directly to the water and stir gently.
Scaling the dosage
1 quart
2 drops
clear
1 gallon
8 drops
clear
5 gallons
40 drops
clear
Double all figures for cloudy water.
Stir to mix the bleach throughout the water. Let stand for a minimum of 30 minutes at room temperature before drinking. Cold water requires longer contact time — in water below 40°F, extend contact time to 60 minutes. The chlorine needs time to reach and kill pathogens throughout the water volume.
After 30 minutes, the water should have a faint chlorine odor — similar to a lightly chlorinated pool. This smell indicates active chlorine is present and the treatment was effective.
If there is no chlorine smell: repeat the dose and wait another 15 minutes. Check again. If still no smell after the second dose, do not drink the water — organic contamination may be consuming the chlorine faster than it can disinfect, or the bleach may be too degraded to be effective.
Treated water can be recontaminated by dirty hands, unclean containers, or exposure to the open air over time. Store in a clean, sealed container. Use within 24 hours if kept at room temperature, or refrigerate for longer storage. Label with the treatment date and time.
Know the limits
Cryptosporidium parvum is chlorine-resistant at household dosages. For water with suspected Crypto (floodwater, agricultural runoff, surface water downstream from livestock), use boiling or a certified filter instead.
Chlorine does not remove industrial solvents, agricultural chemicals, petroleum products, heavy metals, or other chemical contaminants. In a chemical contamination event, do not treat and drink — use stored water only.
Bleach does not clarify or filter turbid water. Pre-filtering is required before treatment — and sediment remaining in the water after treatment may harbor pathogens shielded from the chlorine.
Heavy metals are not affected by chlorine treatment. If your water source has lead or arsenic concerns, bleach disinfection does not help. Use an NSF 53-certified filter for those specific contaminants.
Cyanotoxins from harmful algal blooms are not removed by chlorine treatment. If a HAB advisory is in effect, do not use that water source regardless of treatment method.
Bleach stored for more than 1–2 years may have insufficient concentration to reliably disinfect. If the bleach bottle was purchased more than a year ago and has been stored in a warm location, replace it. When in doubt, boil the water instead — heat is independent of chemical concentration.
Reference card
A laminated copy of this card attached to your stored water containers means the protocol is available when it's needed — without searching for it online. The print button below opens just the card for printing.
New World Survival
Use only: regular, unscented bleach — 6–8.25% sodium hypochlorite (NaOCl)
NOT: scented, splashless, color-safe, or bleach with added cleaners
Clear water
8
drops per gallon
≈ 1/8 teaspoon
Cloudy water
16
drops per gallon
Pre-filter first
Pre-filter if cloudy — pour through cloth or coffee filter
Add bleach — 8 drops per gallon (clear) or 16 drops (cloudy)
Stir and let stand 30 minutes (60 min if water is cold)
Check smell — faint chlorine odor = effective. No smell = repeat dose, wait 15 min more. Still no smell = do not drink.
Store sealed — use within 24 hours at room temperature
Bleach does NOT remove
Cryptosporidium · chemicals / fuel · heavy metals · sediment · algal toxins
For chemical contamination: use stored water only. For Crypto: boil instead.
newworldsurvival.com/self-reliance/water/bleach-water-disinfection/ · Source: EPA Emergency Disinfection of Drinking Water
Dosage scaling
| Volume | Clear water (drops) | Cloudy water (drops) | Approx. teaspoons (clear) |
|---|---|---|---|
| 1 quart | 2 | 4 | 1/32 tsp |
| 1 gallon | 8 | 16 | 1/8 tsp |
| 2 gallons | 16 | 32 | 1/4 tsp |
| 5 gallons | 40 | 80 | 5/8 tsp |
| 7 gallons | 56 | 112 | ~7/8 tsp |
| 15 gallons | 120 | 240 | ~2 tsp |
| 55 gallons | 440 | 880 | ~7 tsp (~2.5 tbsp) |
Based on 6–8.25% sodium hypochlorite and standard drop size of approximately 1/16 teaspoon per 8 drops. Double all figures for cloudy water. For the 55-gallon drum, use water preserver concentrate (designed for large-volume treatment) rather than household bleach — it doses more accurately at this scale.
Choosing the right method
Use bleach when:
Use boiling or other methods when: