Home / Water

Water bag: carry and store water in something that folds flat when empty

By the Plain Prepper editors. Updated 2026-10-15.

We research products from makers' specs, manuals and safety agencies; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.

Quick answer

A collapsible water bag holds liters of water when full and folds small when empty, which suits evacuation kits, camping and refilling from a filter. CDC says to store at least 1 gallon per person per day for 3 days, use food-grade containers, and replace self-stored water every 6 months. MSR's Dromedary bags come in 4, 6 and 10 L sizes with a 1,000-denier shell and a food-grade lining; Platypus's Platy 2 L bottle weighs 1.3 oz.

Three collapsible water bags compared

Spec	MSR Dromedary	MSR DromLite	Platypus Platy 2.0L
Sizes	4, 6 and 10 L	2, 4 and 6 L	2 L (70 fl oz)
Build	1,000D fabric, food-grade polyurethane lining	Rugged film, RF-welded seams, food-grade lining	Nylon and polyethylene film
Cap	3-in-1 fill, drink and pour	3-in-1 fill, drink and pour	Threaded; takes Platypus caps or drink tube
Carry	Perimeter webbing for carrying and hanging	Top loop to hang and carry	Flat bottle
Temperature	Freezing to boiling, per MSR	Handles freezing	Not stated
Empty size	Collapsible	Folds to the size of its cap	13.8 x 7.5 in, 1.3 oz

All three list BPA-free materials; Platypus adds BPS-free and phthalate-free.

How much water a bag holds, in days

CDC's minimum is 1 gallon per person per day for 3 days, about 11.4 liters per person. With 1 gallon at about 3.785 L:

• 10 L Dromedary: about 2.6 gallons, roughly 2.6 person-days.
• 6 L bag: about 1.6 gallons.
• 2 L Platy: about half a gallon, a day's drinking water on the move.

Weight adds up fast: USGS puts water at 8.34 pounds per gallon, so a full 10 L bag weighs about 22 pounds before the bag itself. Carry less and refill through a filter when you can.

Sizing for a household

Using CDC's 1 gallon per person per day, a household of four needs 12 gallons for 3 days, about 45 liters. That is about four and a half 10 L Dromedary bags, or five to be safe, weighing roughly 100 pounds in water if all filled at once. One practical split: keep most stored water in rigid containers at home and use bags for the portable share: one 4 to 6 L bag per person in a go bag, and an empty DromLite or two folded in the kit for refilling later. Adjust upward for hot weather, illness, pregnancy or pets, which CDC notes need more.

Before the first fill

Sanitize a new or stored bag before filling it with drinking water. CDC's method uses unscented household bleach diluted at 1 teaspoon per quart, shaken over every inside surface and poured out after at least 30 seconds; our water storage containers guide walks through the full routine. For soft bags specifically:

• Open the widest opening: MSR's 3-in-1 cap has a fill mode as well as drink and pour modes; use the fill opening for rinsing.
• Dry hanging: use the Dromedary's webbing or the DromLite's loop to hang the bag upside down with the cap off.
• Keep dirty and clean bags apart: mark one bag for untreated water if you fill from streams.

Storing water in a bag

• Date it and rotate: CDC says to replace water you filled yourself every 6 months.
• Cool, dark and clean: CDC recommends 50 to 70°F, out of direct sunlight, away from gasoline and pesticides.
• Freezing: MSR says both Dromedary and DromLite linings handle freezing, useful for a vehicle kit in winter.
• Bulk reserves: bags are best for carrying and short-term storage; for a 2-week household reserve, see our emergency water storage guide.

Pairing a bag with a filter

Soft bags pair well with filters for refilling from streams or rain barrels. Platypus says its Platy bottle can be used with its GravityWorks and other filters. CDC's advice for questionable water is to boil it, or filter and then disinfect it. Keep separate bags for dirty and clean water, and label them. See our portable water filter and Sawyer Squeeze guides for filter choices.

What to look for when you buy

Questions people ask

What is a water bag used for in emergencies?

Carrying and storing water in a container that folds small when empty, for evacuation kits, camping or refilling from a filter.

How long can water be stored in a water bag?

CDC says to replace water you filled yourself every 6 months and to keep it at 50 to 70°F out of sunlight.

How do I clean a water bag?

CDC: wash with soap, rinse, sanitize with 1 teaspoon of unscented bleach per quart of water, shake, wait 30 seconds, pour out and air-dry.

How much water should I store per person?

CDC says at least 1 gallon per person per day for 3 days, and a 2-week supply if possible.

Sources

• How to Create an Emergency Water Supply, Centers for Disease Control and Prevention
• Dromedary Bags, MSR (Cascade Designs)
• DromLite Bags, MSR (Cascade Designs)
• Platy 2.0L Bottle, Platypus (Cascade Designs)
• A million gallons of water: how much is it?, U.S. Geological Survey
• About Water Treatment Options When Hiking, Camping, or Traveling, Centers for Disease Control and Prevention

Sources checked 2026-10-15.