A water reserve must fit both your household and its storage space. Calculating a volume is only the start: you need to carry the containers, open them cleanly and replace their contents when required. This guide distinguishes German BBK guidance from US CDC recommendations and helps turn them into a storage plan.

How much water should I plan for?

Germany: BBK guidance uses 1.5 litres of daily fluid for adults plus 0.5 litres of cooking water, aiming for ten days with three days as a useful start. USA: CDC guidance recommends at least one US gallon per person per day for three days, with two weeks if possible. One US gallon is about 3.8 litres. These figures have different planning scopes. Use your country's guidance and account for individual additional needs rather than treating both figures as equivalent minimum drinking quantities.

YOUR WATER PLAN

Calculate your water reserve

Enter your household size, planning period and water already stored. This calculation stays in this browser and is not saved.

BBK: 2 L per person per day, including 0.5 L for cooking. Aim for 10 days; even 3 days helps. Plan hygiene and other needs separately.

1–100, whole number
1–365, whole number
0–1,000
0–1,000,000

The extra amount is for the whole household each day, for example pets, additional hygiene or preparation. Do not count amounts already included in your basis twice. 0 L is only the starting value, not a needs recommendation.

Your quantity plan

Base amount
40 l
Extra amount
0 l
Total planned
40 l
Still to provide
40 l

2 × 10 × 2 l + 0 l × 10 = 40 l

The water weighs roughly the same number of kilograms, plus containers. Check storage space, carrying weight and separate storage locations. Results are rounded to two decimal places.

These approaches cover different uses and are not interchangeable. Account separately for individual additional needs and local guidance; this tool does not determine personal drinking requirements.

Basis checked 9 October 2026: BBK, preparing for crises and disasters (pp. 6–7, German) · CDC, emergency water supply (USA)

A calculation you can understand later

Write down what each number includes: people, days, daily allowance and additional uses. Using the German planning figure, two adults multiplied by three days and two litres gives twelve litres for drinking and cooking. Another large container is not automatically the next step; first account separately for pets and other household needs. Distinguish the reserve from stock already being used. When a bottle comes out of the reserve, put that exact quantity on the restocking list.

Sealed bottles or containers you fill yourself?

The CDC prefers unopened commercially bottled water. Water you fill yourself needs suitable food-grade containers and should be replaced every six months. Former chemical containers are unsuitable. For your plan, choose deliberately between sealed bottles and containers you maintain yourself. Keep package information and cleaning instructions with the reserve. Before filling a container, read the complete CDC and manufacturer guidance. Buying a container alone does not resolve how it must be prepared.

Choose the storage location before the container size

Measure the width, depth and height of the storage area and consider the route to it. A container must be removable when full, not merely fit through the opening when empty. CDC storage guidance calls for a cool location away from direct sunlight and chemicals. If you divide the supply between locations, put them on the same inventory. This helps prevent half the water being forgotten behind another cupboard. Use labels everyone can understand in shared storage areas.

Carrying and dispensing are part of the decision

A litre of water weighs roughly one kilogram, with the empty container's weight on top. Choose a fill volume you can manage rather than automatically selecting the largest capacity. Smaller units are easier to distribute and open separately. A larger container may work at a fixed dispensing spot when its handle, outlet and supporting surface suit the location. The linked Aqua-Tainer is an example of a large container. Its capacity does not establish whether you can move it when full or use it cleanly in your storage space.

Rotate using one inventory card

A simple inventory card needs four details: container or bottle count, volume, location and next check or replacement date. Add the filling date for water you store yourself. At each check, inspect the closure and exterior and replace damaged containers according to their instructions. A calendar reminder is useful only if you update the inventory afterwards. Keep the card somewhere other household members can consult without needing access to a particular app, such as beside the shelf.

What this reserve does not do

A filled container does not treat water. An outdoor filter is not a universal solution to every possible contaminant either. Read the specific local water notice: a boil-water advisory and a do-not-use notice may require different actions. Record your water supplier's contact and information channels in advance. That avoids searching for both containers and the responsible authority during a disruption. Use your known safe reserve in accordance with official guidance when the situation is uncertain.

FAQ: Is one large container better than several bottles?

It depends on carrying ability, space and dispensing. Calculate the total volume first, then divide it into manageable units. A combination may work if small bottles for travel and a container in a fixed position serve different purposes. Capacity alone is not a measure of quality.

FAQ: Must I buy the entire target reserve at once?

You can build gradually. Record the existing quantity, the next useful addition and the longer-term target. Add manageable amounts through normal shopping and check the storage space early. A small, maintained reserve is a concrete start; keep the missing quantity visible on your list.

Sources and review dates