Eight Litres Each: The Water Gap Nobody Plans For

A few years ago on a rough, offtrack route in central Tasmania, we each carried eight litres (around 18 lbs) of water across a boulder-strewn ridge that had to last us the next 48 hours.

Eight kilos. On top of everything else. Nobody enjoyed it, but it was still the right call.

Water is the one thing on a multi-day hike you cannot improvise your way out of. It is also the one line most trip plans leave blank.

Most people drink when they are thirsty. On a long hot day, that is already too late. By the time thirst shows up, you are already behind, not getting low.

The fix is almost embarrassingly simple. Drink on the clock, not on thirst. Work out roughly how much you need for the day, split it across set check-ins, and sip on schedule whether you feel like it or not.

The reason this matters more than people think is what dehydration takes first. It is not your legs. It is your judgement. That foggy 3pm feeling where the map stops making sense and you start making sloppy calls about camp, or the weather, or whether to push on.

Before you leave home, decide your check-in intervals. Every hour, or every break, whichever you will actually stick to.

Here is the shift that changed how I plan water.

Do not work out how much water the trip needs. Work out the longest stretch between two sources you would genuinely bet on, then carry for that.

That is why we each shouldered eight litres on this trip. It was not that the whole route was dry. It was that one section had no reliable water in it, and the only sensible number to plan against was the worst realistic gap.

Heavy, yes. But the alternative is arriving at a dry creek bed at four in the afternoon with an empty bladder and no plan B.

On your next route, mark every water source, then mark the longest gap between two you would actually bet on. Carry for that gap, not for the average.

Creeks marked in blue dry up. Tanks run empty. A late-season map is a different map to the one you printed in spring, even though it looks identical.

So the rule I hold to is simple. Never assume a source is running. Ask someone who has been there recently, check the park notes, and plan as though the least reliable source on your list will not be there.

If it is flowing when you arrive, brilliant, you have a light afternoon. If it is not, you already knew what to do.

That is the whole game with water. You are not trying to predict it. You are trying to make sure the wrong answer is survivable.

There is one thing worth saying about the other direction.

On hot days, especially long ones, you can drink enough water and still feel wrong. Flat, cramping, foggy in a way that does not quite match dehydration. Often that is not a water problem. It is a balance problem.

When you sweat heavily you are not just losing fluid. You are losing electrolytes, and water alone does not replace them. Drink enough without replacing those and you can tip yourself into a different kind of trouble.

The fix is simple. Carry electrolytes on any trip where heat or exertion is a real factor, and use them. Tablets, powder, whatever format you will actually remember to take. The goal is not just to stay hydrated. It is to keep your body in balance so it can actually do the work you are asking of it.

THAT’S ALL FOR THIS WEEK

Thanks for reading Mowser’s Musings. I hope this helps you hike further and happier.

Until next week, keep exploring.

Mowser

Discover more. Hike further.

P.S. If your water plan lives in your head rather than somewhere you can actually check before you leave home, that is one of the things I have been building PeakBound to solve. The waitlist is where the real build updates go. peakbound.app