Measuring and sharing water within a group

The body is constantly losing water: through sweat, through moist breath and through urine and stool. This water has to be replaced, or performance drops and later it becomes dangerous. How much someone needs depends heavily on heat, exertion, body size and health – there is no single figure for everyone.

The core principle of sharing water is therefore: reduce losses instead of cutting drinking water. Someone resting in the shade instead of working in the midday sun sweats much less and makes the same supply last far longer without taking anything away from the body. A principle from survival manuals puts it roughly like this: water belongs in your body, not in your bottle.

Savings are made where they do no harm: on washing up, on personal washing and on cooking. A pot of pasta needs a lot of water; a ready meal that is only heated needs little. Washing also works with a damp cloth and a bowl instead of running water.

The first step is honest counting. Every container is recorded with its volume, split into treated drinking water and raw water, and the total is written down. Guessing is not enough, because a half-full jerrycan often looks fuller than it is. Then you think about when resupply or help can realistically arrive, and plan a reserve.

Next you set a clear order: drinking water first, then water for infant formula and medication, then cooking, hygiene last. Labelled containers (‘drinking’, ‘cooking’, ‘washing’) stop drinking water from being used up on the washing-up.

Sharing fairly means by need – not equal for everyone and not by who is loudest. People doing physical work, the sick, those who are pregnant or breastfeeding and small children need special attention. Each person gets a marked bottle that is refilled at fixed times. That way everyone sees what they have, and secret extra drinking stops.

A water plan is worthwhile wherever resupply is uncertain: during a long water-supply outage at home, on trips without safe sources, or when a vehicle breaks down in a remote area. The earlier you plan, the more room you have.

No plan replaces resupply. If the stock will not last despite all the saving, the main goal is to get help in time, go to a distribution point or open up a new source and treat its water. Drinking untreated water because water is short is no solution: diarrhoea costs more water than you saved.

Dehydration creeps up. Early signs are thirst, dark and infrequent urine, headache, dizziness and unusual tiredness. Anyone showing these signs gets water – even if the plan says something else at that moment. The plan exists for the people, not the other way round.

In heat and with exertion things can move very fast. Confusion, severe weakness, impaired consciousness or no urine at all are emergency signs: call the local emergency number (112 in the EU) immediately. Avoid alcohol, because it puts extra strain on the fluid balance, and very salty foods increase thirst.

Keep an eye on mood and conflict too. Shortage makes people irritable. One person keeping track, numbers that everyone can see and clear rules take a lot of pressure out of the situation. Anyone who feels treated unfairly says so openly instead of taking water in secret.

Humanitarian minimum standards such as the Sphere Handbook give planning figures for drinking, cooking and hygiene. They are guide values for planning for large groups, not a rule for how much one person should drink on a hot day.

A simple tally on the fridge door or a notebook is enough as a tool. Noting daily what has been used shows early whether the supply will last, so you can act in time.