Blackout Kit · Water
Emergency Water Storage and Filters: How Much to Store and How to Treat It
CDC's gallon-per-person-per-day rule, how to store and rotate water, and which filters remove what.
By PowerLockdown EditorialUpdated October 27, 20263 min readHow we research
In this guide
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Long outages can affect water as well as power: homes on wells lose their pump, and municipal systems can issue boil-water notices when treatment or pumping is disrupted. Stored water is the cheapest, most reliable insurance in a blackout kit.
This guide uses CDC and Ready.gov guidance for the numbers and manufacturer pages for product specs. It is research-based; we do not test products.
How much water to store
CDC: "Store at least 1 gallon of water per person, per day for 3 days." CDC adds: "Try to store a 2-week supply if possible." Ready.gov uses the same gallon-per-person-per-day figure "for drinking and sanitation" for several days.
CDC also says to consider storing more for pregnant women, people who are sick, pets, or if you live in a hot climate.
- Family of 4, 3 days: 4 × 3 × 1 = 12 gallons
- Family of 4, 2 weeks: 4 × 14 × 1 = 56 gallons
- Add extra for pets and hot weather
Storing and rotating water
CDC recommends FDA-approved food-grade water storage containers. Commercially bottled water is the simplest option; keep it in its original sealed packaging. If you fill your own containers, CDC says to replace the water every 6 months, and Ready.gov gives the same six-month rule for water that has not been commercially bottled.
Store containers somewhere cool and dark, off concrete floors if possible, and away from fuels or chemicals. A full 7-gallon jug weighs close to 60 lb, so store large containers where you can use a spigot rather than lifting them.
Treating water: boil, disinfect, or filter
CDC: "Bring clear water to a rolling boil for 1 minute (at elevations above 6,500 feet, boil for 3 minutes)." Boiling needs a working stove, which is why a disinfection fallback matters in a blackout.
For bleach, CDC says to use unscented household liquid chlorine bleach (typically 5% to 9% sodium hypochlorite in the U.S.). For clear water add 8 drops per gallon; for cloudy water, 16 drops per gallon. Stir and wait 30 minutes before drinking.
Research-based picks: containers and filters
Two ways to store water and four ways to treat it. Claims below are quoted from manufacturer pages, checked October 27, 2026.
No. 1Water storage
Reliance Jumbo-Tainer 2.0, 7 Gallon (08630-03)
Best for: Rigid, refillable storage you can rotate
- 7 gal / 26 L
- 15.3 × 8.5 × 18.0 in; 2.9 lb empty
- Food safe: LFGB certified and FDA compliant
- PFAS- and BPA-free
- Leak-proof hideaway spigot; dual handles
Tradeoffs
- Reliance does not list it as stackable
- About 58 lb when full (7 gal × ~8.3 lb plus container)
No. 2Water storage
waterBOB Bathtub Emergency Water Storage
Best for: Filling a large volume fast when a storm is forecast
- Holds up to 100 gallons
- 10 mil food-grade LLDPE liner
- Fills in about 20–30 minutes
- Siphon pump included
- Designed for one-time use
Tradeoffs
- Single use
- Manufacturer notes most standard bathtubs hold about 60–70 gallons, so real capacity is often lower
No. 3Water filter
MSR AutoFlow XL Gravity Filter 10 L
Best for: Filtering water for a whole household if tap water is unsafe
- 10 L reservoir; hang it and gravity does the filtering
- 1.75 liters per minute; cartridge rated for 1,500 liters
- 0.2-micron hollow fiber: removes bacteria (99.9999%) and protozoa (99.9%) per MSR
- Meets EPA standards and NSF Protocol P231 for bacteria and protozoa (manufacturer claim)
- 12 oz; not effective against viruses or chemicals (maker)
Tradeoffs
- Not rated for viruses or chemicals. CDC advises disinfecting filtered water when viruses are a concern, and no filter makes fuel-contaminated water safe.
- Flow slows as the bag empties
No. 4Water treatment
Sawyer Squeeze Water Filter System (SP129)
Best for: Reusable all-rounder: squeeze, gravity or on a bottle
- 0.1-micron absolute hollow-fiber filter
- Removes 99.99999% of bacteria and 99.9999% of protozoa such as Giardia and Cryptosporidium (manufacturer)
- Filter about 3 oz
- Reusable BPA-free collapsible pouch
- Lifetime limited warranty
Tradeoffs
- No virus claim: disinfect after filtering if viruses are a concern
- Manufacturer page lists no filter life in gallons
No. 5Water treatment
LifeStraw Personal Water Filter
Best for: A light backup filter for every go-bag
- 0.2-micron membrane
- Removes 99.999999% of bacteria and 99.999% of parasites (manufacturer)
- Up to 1,000 gallons (4,000 L)
- 1.6 oz (46 g)
- Unlimited shelf life unused (manufacturer)
Tradeoffs
- No virus claim; not for chemicals or heavy metals
- You drink from the source, so it does not fill containers
No. 6Water treatment
Katadyn Micropur MP1 Water Purifier Tablets (20 tablets)
Best for: A purifier backup that covers viruses as well as bacteria and cysts
- Chlorine dioxide tablets: one tablet treats 1 liter of clear water
- 20 tablets treat up to 20 liters (a 30-tablet pack is also sold)
- Effective against bacteria, viruses and cysts such as Giardia and Cryptosporidium (EPA-registered label)
- 4-hour treatment time; react in an opaque container or in the dark
- Shelf life 5 years from date of manufacture (manufacturer)
- EPA Reg. No. 70060-22-39444
Tradeoffs
- Four hours per liter is slow for a household; use it for drinking water, not bulk
- Small volume per pack: 20 liters is about 5 gallons
Water checklist
- 1 gallon per person per day: 3 days minimum, 2 weeks if possible (CDC)
- Extra for pets, illness, pregnancy and hot weather
- Food-grade containers, labelled with the fill date
- Unscented household bleach and a dropper
- A filter plus a way to disinfect after filtering
- Calendar reminder to rotate self-filled water every 6 months
Frequently asked questions
- How much water should I store for a power outage?
- CDC says at least 1 gallon per person per day for 3 days, and to try for a 2-week supply if possible. Store more for pets, sick or pregnant household members and hot climates.
- How often should I replace stored water?
- CDC and Ready.gov say to replace water you bottled yourself every 6 months. Keep commercially bottled water sealed and check its date.
- How much bleach do I add to a gallon of water?
- CDC: 8 drops of unscented household bleach (5–9% sodium hypochlorite) per gallon of clear water, 16 drops for cloudy water, then wait 30 minutes.
- Does a water filter make water safe from viruses?
- Usually not. CDC notes most portable filters do not remove viruses. Choose a filter that specifically claims virus removal, or filter and then disinfect.
Sources
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