Camper trailer water planning for a family trip: how many litres to carry

Working out how much water to carry on a family camper trailer trip comes down to four numbers: a drinking allowance for each person, everything else you use water for, a reserve sized to how far you are from resupply, and the weight all of that adds to the trailer. Because one litre of water weighs one kilogram, the litres you settle on are also kilograms of payload — which is why camper trailer water planning belongs alongside packing and weighing, not as an afterthought at the tap.

This guide sets out the published Australian figures for drinking water, the allowances state agencies use for remote travel, a worksheet that turns them into a carrying total, and the health-department rules for treating water you did not bring yourself. It is desk research for Australian conditions, and it deliberately does not tell you what a family “usually” uses, because that number is yours to measure.

Start with drinking water, one person at a time

The Better Health Channel, run by the Victorian Department of Health, publishes adequate daily fluid intakes by age and sex. They are the figures to use for the drinking line of the worksheet.

Person	Adequate daily fluid intake
Infant 0–6 months	0.7 L, from breastmilk or formula only
Infant 7–12 months	0.8 L total, of which 0.6 L as fluids
Child 1–3 years	1 L
Child 4–8 years	1.2 L
Girl 9–13 years	1.4 L
Boy 9–13 years	1.6 L
Girl 14–18 years	1.6 L
Boy 14–18 years	1.9 L
Woman 19 years and over	2.1 L
Man 19 years and over	2.6 L
Pregnant woman 19 years and over	2.3 L
Breastfeeding woman 19 years and over	2.6 L

Three qualifications matter for a camping trip. These intakes include all fluids, though Better Health Channel says it is preferable that the majority comes from plain water. They are baselines: the same page says people need more when they are physically active, exposed to warm or hot conditions, or vomiting or have diarrhoea. And they are drinking figures only — nothing for cooking, washing up, hand washing or teeth.

For a family of two adults and two children aged six and eleven — using the girls’ figure for the older child — the baseline drinking line is 2.6 + 2.1 + 1.2 + 1.4 = 7.3 litres a day before any allowance for heat or exertion. Written down that way, it is obvious that a single 10 litre container is not a day’s drinking water for four people.

What state agencies say to carry in remote areas

Drinking intake is the floor. Agencies responsible for outback travel publish all-purpose carrying allowances that are considerably higher, because they include cooking and hygiene and assume you may be stranded.

Source	Allowance	Reserve
Landscape South Australia, SA Arid Lands	6 L per person per day in mild weather; 10 L per person per day in warmer weather	“Adequate supplies of water (plus a three to four day reserve supply)”
Western Australia Police Force	3 L per person per day, “and allow for extra water for car breakdowns”	Extra for breakdowns; distribute water through the load rather than in one place
Get Ready Queensland	4 L per person per day in the road-trip emergency kit	20 L for emergency use

These figures are not in conflict; they answer different questions. The WA Police figure is a survival minimum for the vehicle, the SA figure is a planning allowance for everything you do with water in the arid zone, and the Queensland figure sits in a road-trip emergency kit. For camper trailer water planning the useful move is to adopt the one whose assumptions match your trip. A sealed-road weekend two hours from a town is not an SA Arid Lands trip; a week beyond the bitumen in summer is, and 10 litres per person per day plus several days’ reserve is the number to plan around.

Camper trailer water planning: the worksheet

Build the total in five lines. Only the first line comes from a published table; the rest come from your own measurement, which is why a shakedown trip close to home is worth doing with a marked container before anything remote.

1. Drinking. Sum the adequate intakes for everyone travelling. If the forecast is hot or the days are active, increase it — Better Health Channel gives no figure, but the SA Arid Lands move from 6 to 10 litres per person per day between mild and warm weather gives a sense of scale.
2. Cooking and food preparation. Depends on the menu. Boiling pasta and rinsing salad use water; a dinner cooked in a single pan barely does.
3. Washing up, hand washing and teeth. The largest variable. A bucket-and-basin routine can be measured in a single evening at home.
4. Reserve. Sized to the distance from resupply. One extra day is reasonable where a town is an hour away; SA Arid Lands recommends a three to four day reserve for the outback.
5. Other. Pets, rinsing sandy feet, a solar shower if you carry one.

Here is the arithmetic for the example family — two adults, children aged six and eleven — on three nights in mild weather at a campground with no drinking water, two hours from the nearest town. The drinking line is sourced; the other lines are placeholders to show the method, not a measurement of any family.

Line	Daily figure	Three days
Drinking, baseline (2.6 + 2.1 + 1.2 + 1.4)	7.3 L	22 L
Cooking (placeholder)	4 L	12 L
Washing up, hands, teeth (placeholder)	10 L	30 L
Reserve: one extra day of the above		21 L
Total to carry		85 L

Eighty-five litres is 85 kilograms, and that conversion is the point of the next section.

Litres are kilograms: fit the water into the payload

The NSW Government’s dogging and rigging glossary states it plainly: “One litre of water weighs one kilogram.” A full 80 L tank is 80 kg; four 20 L jerry cans are 80 kg plus the containers. Neither is trivial against a camper trailer’s payload.

Three consequences follow.

Weigh the trailer with the water you will actually carry. The four-reading weighing method only tells you the truth if the tank and containers are at travelling levels. A weigh with the tank empty and a trip with it full are two different trailers.

Put the weight where the towing guidance says. NSW Government towing guidance says loads “should be kept as low and as close as possible to the axle or axles with about 60 per cent of the total weight forward of the centre of the axle or axles”, and that about 5–10 per cent of the total mass of trailer plus load should be supported by the vehicle through the coupling. A built-in tank is fixed and you cannot move it; jerry cans are movable ballast, and where you put them changes the ball weight. The principles are covered in keeping heavy gear low.

Do not put it all in one place. WA Police’s outback advice is to “distribute it in smaller amounts throughout the load” rather than store all water in one place. The practical reason is failure: one split tank or one dropped container should not take the whole supply with it. Splitting the supply also lets you keep drinking water in dedicated containers and use the tank for washing, which simplifies treatment decisions later.

If the total will not fit in the payload, the answer is to shorten the interval between refills or reduce non-drinking use, never to shave the drinking or reserve lines. The payload guide covers what else can give.

Is the water where you are going drinkable?

NSW National Parks and Wildlife Service is blunt about its campgrounds: “Drinking water isn’t available at most campgrounds. Check before you arrive.” The same applies more widely. A tap, a rainwater tank or a creek at a campsite is a source of water; it is only a source of drinking water if the manager says so. If you cannot confirm that before departure, plan as though the site has none, which is what the worksheet above assumes.

Where the supply is unknown or a boil-water alert applies, NSW Health’s instructions are the ones to follow. Water for drinking or food preparation “should be brought to a rolling boil to make it safe”, and kettles with automatic shut-off switches can do this. Let it cool and store it in a clean container with a lid. NSW Health says bottled or cooled boiled water should be used for drinking, washing uncooked food such as salad vegetables and fruit, making ice, cleaning teeth, gargling and pets’ drinking water, and that infant formula should be made with cooled boiled water. The Victorian Department of Health gives the same instruction: bringing water to a rolling boil and letting it cool should inactivate any pathogens.

If you cannot boil, NSW Health says unscented household bleach containing 4–5% available chlorine may be used: 2 drops per litre, or 4 drops if the water is cloudy, mixed well and left to stand for 30 minutes at 25 °C — one hour at 15 °C, or two hours at 5 °C. Chlorine purification tablets may also be used. Note the temperature clause; a cold morning changes the waiting time, not the dose. Follow the instructions on the tablets you carry rather than a generic rule.

NSW Health’s rainwater guidance adds a group to think about. People with a severely weakened immune system should talk to their doctor about the risks of drinking rainwater. If anyone in the family is in that position, the safe default is to carry all drinking water rather than rely on treatment.

Keeping the trailer’s own water clean

Water that was fine going in can be unpleasant coming out if the tank, lines and pump have been neglected. Two rules apply regardless of brand; the procedure itself belongs to the manufacturer.

Fill only through a food-grade hose. Mars Campers, a camper trailer manufacturer, makes this the first step of its tank-cleaning advice: use only a food-grade hose, not a garden hose. Carry your own so you are not dependent on what hangs on the campground tap.

Follow your manufacturer’s sanitising procedure. Mars Campers’ published method for its own trailers is a bleach solution mixed in a bucket, added to the empty tank, topped up with fresh water, run through the taps for one to two minutes, left for several hours and then flushed thoroughly, followed by a bicarbonate of soda rinse; it also offers a bicarbonate and vinegar alternative and warns not to combine the two methods, because bleach and vinegar must never be mixed. That is one maker’s procedure for one maker’s tanks. Yours may specify different products, or forbid chlorine near a particular pump or filter, and the manual overrides anything you read here.

For reference, health departments publish tank disinfection figures for household rainwater tanks: NSW Health says about 5 milligrams of chlorine per litre disinfects a tank, equivalent to 40 millilitres of sodium hypochlorite or 7 grams of calcium hypochlorite per 1000 litres, with at least 0.5 milligrams per litre of free chlorine remaining 30 minutes later. The Victorian Department of Health gives the same target and adds that you should wait at least 24 hours after chlorinating. They are household-tank figures; a camper’s tank is a fraction of that volume, so use the trailer maker’s dose rather than scaling them yourself. Victoria’s warning applies at any size: never climb into a tank.

Before departure, drain and refill a tank that has been sitting, run every tap until the water is clear, and check the pump draws properly — its draw is part of the 12V load budget, and its failure removes access to the tank.

Children, heat and the signs to watch

Families plan water differently because children dehydrate faster and cannot always say so. NSW Health’s hot-weather guidance says babies and young children can overheat and dehydrate quickly. For babies under six months, it says they may need or demand extra feeds during hot weather; for breastfed babies, breast milk provides for their needs and extra water is not necessary; for bottle-fed babies, the number of feeds may need to be increased. For older babies and children, NSW Health says to offer extra drinks in hot weather and that the best drink is water.

The Royal Children’s Hospital Melbourne lists the signs to watch. Mild dehydration: thirst and urinating less than usual. Moderate: thirst, being less active and quieter, cool hands and feet, dry mouth, lips and tongue, and darker, less frequent urine. Severe: cold hands and mottled skin, lethargy and unusual sleepiness, sunken eyes and very little or no urine. RCH says severe dehydration is serious, can worsen quickly and needs medical help fast, and that a baby under six months showing any sign of dehydration should see a doctor.

Practical translations for a campsite:

• keep a child’s own drink bottle within reach and refill it in front of them, rather than waiting for a request;
• count wet nappies and note urine colour — NSW Health uses both as dehydration signs;
• carry oral rehydration solution in the first-aid kit, which RCH describes as the best fluid for treating dehydration in children;
• decide before the trip where the nearest medical help is and how long it takes to reach, and build that into the reserve line.

Wash water and where it goes

Greywater is part of the water plan because every litre you use for washing has to go somewhere, and where it goes is regulated by the land manager. Parks and Wildlife Service Tasmania’s Leave No Trace guidance is representative: wash up using hot water, preferably without soap or detergent, and strain and scatter the washing-up water 50 metres from water sources; wash your body at least 50 metres from water sources; camp at least 50 metres from lakes and streams. Other land managers set their own distances and methods, so confirm the rule for the site rather than carrying one number between states. Caravan parks set their own rules too — ask at check-in.

For a camper trailer this means a collapsible bucket or a greywater container is part of the kit, not an option, and the washing-up routine in the kitchen packing checklist should end with disposal, not with the last clean plate.

Water routine before departure and on arrival

Before leaving:

1. Confirm with the campground or land manager whether drinking water is available, and treat “unsure” as “no”.
2. Total the worksheet in litres, convert to kilograms and confirm the trailer’s payload absorbs it.
3. Fill through a food-grade hose from a supply you trust; note the date of the last tank sanitise.
4. Split the supply across containers, keep drinking water separate from washing water, and secure every container.
5. Pack the treatment kit: a means to boil, tablets or unscented bleach with a dropper, and the instructions.
6. Pack the greywater kit: bucket or container, strainer, and a plan for where it will be emptied.
7. Add water to the pre-trip checklist — caps, drain valves and pump — so it is inspected every time.

On arrival:

1. Confirm the site’s water status with the manager before anyone drinks from a tap.
2. Set the children’s bottles up first and put the treatment kit where it will be used.
3. Read the site’s rules for greywater and toilet waste before the first wash-up.
4. Note the litres remaining each evening. Three evenings of readings give you the family’s real daily figure, and that number replaces every placeholder in the worksheet next time.

Scope and limitations

This guide is desk research for Australian conditions. The fluid intake table is the Victorian Department of Health’s Better Health Channel presentation of adequate intakes; the outback allowances are Landscape South Australia’s, the Western Australia Police Force’s and Get Ready Queensland’s, each published for its own context. The worked example uses placeholder figures for cooking and washing so the arithmetic is visible; it is not a measurement of any family’s use, and yours will differ.

Water treatment instructions are NSW Health’s and the Victorian Department of Health’s. Tank disinfection doses quoted are for household rainwater tanks, and tank sanitising for a camper trailer should follow the trailer or tank manufacturer — the Mars Campers procedure is one manufacturer’s example, not a universal method. Greywater rules and distances differ between land managers and states; the Tasmanian figures are one service’s requirements. Guidance on children and dehydration is general and does not replace advice from a doctor who knows your child.

Camper trailer water planning for a family trip comes down to a page of arithmetic: sourced drinking figures, measured use, a reserve matched to the distance from help, and the whole total read as kilograms before it is read as litres.