Water is arguably the most critical resource on your Big Lap, yet many caravanners get their water strategy completely wrong. Too little capacity and you’ll be chasing taps every few days. Too much weight and you’ll stress your rig and burn extra fuel. The sweet spot depends on your travel style, rig setup, and where you’re heading.
This guide breaks down the water carrying options available to Big Lappers, from basic jerry cans to sophisticated tank systems. You’ll learn the pros and cons of each approach, how much water you actually need, and which solutions work best for different types of travel.
How Much Water Do You Actually Need?
Before diving into tanks and containers, you need to understand your water consumption patterns. The typical Australian household uses around 200 litres per person per day, but that includes lawn watering, dishwashers, and long showers. Caravan life is different.
Most Big Lappers use between 40-80 litres per day for two people, depending on their habits and setup. Here’s how it breaks down:
- Drinking and cooking: 8-10 litres per day for two people
- Basic washing and hygiene: 15-20 litres per day
- Dishwashing (by hand): 5-8 litres per day
- Shower (3-4 minutes): 12-20 litres per person
- Toilet flushing (if using fresh water): 2-5 litres per day
Track your water usage for the first few weeks of your trip using your tank gauge or by measuring containers. Most people overestimate their needs initially.
Your travel style dramatically affects water needs. Park hoppers who move every 1-2 days can get away with smaller capacity because they’re regularly accessing town water. Free campers who stay off-grid for 5-7 days need much more storage. Remote area travellers heading into places like the Canning Stock Route need maximum capacity plus emergency reserves.
The magic number for most Big Lappers is 3-5 days of water storage. This gives you flexibility to find the next water source without constantly worrying about running dry.
Internal Tank Systems
Built-in water tanks are the gold standard for most caravans. They’re protected from the elements, properly integrated into your rig’s plumbing, and don’t take up valuable storage space. However, not all internal tank systems are created equal.
Single Large Tank vs Multiple Smaller Tanks
Most caravans come with a single large tank, typically 80-120 litres for a mid-sized van. This approach maximises capacity but creates weight distribution challenges. All your water weight sits in one spot, potentially affecting your rig’s balance and handling.
Higher-end vans often use multiple smaller tanks distributed around the chassis. This spreads the weight load and gives you flexibility to partially fill tanks based on your needs. The Lotus Caravans Freedom ~$89,000 uses this approach with two 60-litre tanks positioned at opposite ends of the van.
Tank Materials and Construction
Most modern caravans use polyethylene plastic tanks, which are lightweight, corrosion-resistant, and relatively cheap to replace. Stainless steel tanks last longer and maintain water quality better, but they’re heavier and more expensive. Fibreglass tanks offer a middle ground but can crack if the van flexes too much on rough roads.
~$450
Tank shape matters more than most people realise. Wide, shallow tanks have a lower centre of gravity but slosh more when you’re driving. Tall, narrow tanks create less sloshing but raise your van’s centre of gravity. The best compromise is a moderately wide tank with internal baffles to reduce water movement.
Filling and Monitoring Systems
Your internal tank is only as good as your ability to fill and monitor it. External filling points should be clearly labelled and positioned where you can easily reach them from either side of the van. Many caravanners get caught out by filling points that only work from one side, making some caravan parks impossible to use.
Tank monitoring is crucial for water management. Basic systems use a panel with LED lights showing quarter, half, three-quarter, and full levels. Digital systems give you more precise readings and often include low-water alarms. The CBE MT700 Touch Screen ~$890 is the premium choice, showing exact litres remaining and consumption rates.
External Tank Options
External tanks mounted under your caravan’s chassis offer several advantages over internal systems. They’re easier to access for cleaning and maintenance, don’t take up interior storage space, and can often be retrofitted to existing vans. However, they’re exposed to road debris and weather, and add complexity to your setup.
Underslung Tanks
Underslung tanks mount between your caravan’s chassis rails, keeping the weight low and protected. Quality units use heavy-duty mounting systems that can handle the stress of rough roads and the dynamic load of water sloshing around.
~$650
The main challenge with underslung tanks is ground clearance. Adding a tank under your van reduces clearance by at least 200mm, which can be problematic on rough tracks. Many manufacturers offer low-profile tanks specifically for this application, but you’ll still lose some capability.
Side-Mounted External Tanks
Side-mounted tanks attach to your caravan’s exterior walls or A-frame area. They’re easier to install than underslung units and don’t affect ground clearance, but they’re fully exposed to the elements and potential damage. They also affect your van’s aerodynamics and can look unsightly if not well-integrated.
The biggest advantage of side-mounted tanks is accessibility. You can easily remove them for cleaning or replacement without crawling under the van. Many designs use quick-connect fittings that make removal a 5-minute job.
Portable Water Containers
Portable containers offer maximum flexibility for water storage. You can carry exactly what you need, fill them separately from your main tank, and use them for specific purposes like drinking water or grey water storage. However, they take up valuable storage space and require more active management.
Jerry Cans and Water Cubes
Standard 20-litre jerry cans are the most common portable water solution. They’re cheap, widely available, and easy to handle when full (20kg is manageable for most people). However, they’re not ideal for drinking water storage because the narrow opening makes cleaning difficult and they often retain plastic tastes.
Water cubes are increasingly popular because they stack efficiently and have wider openings for easy cleaning. The downside is they’re more expensive than jerry cans and the square shape can be harder to secure during travel.
Flexible Water Bladders
Flexible water bladders maximise storage efficiency by conforming to available space. When empty, they pack down to almost nothing. When full, they use every cubic centimetre of available space in your storage compartment.
The challenge with bladders is durability and handling. They’re more prone to punctures than rigid containers, and moving a full bladder is awkward and potentially messy. However, for specific applications like emergency water storage or maximising capacity in limited space, they’re unbeatable.
~$89
Large Portable Tanks
For extended remote travel, large portable tanks (50-100+ litres) can significantly extend your water carrying capacity. These typically live in your tow vehicle or on a trailer, giving you the option to leave them at base camp while you explore.
The Kings 100L Water Tank ~$199 is designed to fit in most ute trays and includes a 12V pump for easy transfer to your caravan’s main tank. This setup works well for remote area travel where you need maximum capacity but don’t want to carry the weight permanently.
Weight Distribution and Towing Limits
Water is heavy. A 100-litre tank adds 100kg to your rig when full, and that weight needs to go somewhere. Poor water placement is one of the leading causes of towing problems and caravan instability.
Never exceed your caravan’s ATM (Aggregate Trailer Mass) or your tow vehicle’s towing capacity. Water weight counts towards both limits and can quickly push you over the legal limit.
Ball Weight Considerations
Water stored ahead of your caravan’s axle increases ball weight, while water behind the axle decreases it. The ideal ball weight is 10-15% of your van’s total weight, and water placement can dramatically affect this figure.
A 100-litre tank mounted 1 metre ahead of the axle adds roughly 100kg to your ball weight. The same tank 1 metre behind the axle reduces ball weight by about 50kg. Most caravans are designed with their main water tank positioned to maintain proper ball weight when full, but adding extra tanks can upset this balance.
Axle Loading and Suspension
Your caravan’s axles have weight limits that you cannot exceed safely or legally. Water weight affects both individual axle loads and total mass. Single-axle vans are particularly sensitive because all the water weight goes to one axle.
Tandem-axle vans distribute weight better, but the position of your water tanks affects individual axle loading. Tanks positioned between the axles load both axles equally, while tanks at the front or rear bias the load towards one axle.
Get your van weighed at different water levels to understand how tank placement affects weight distribution. Many caravan dealers offer weighing services, or you can use public weighbridges.
Water Quality and Filtration
Carrying water is one thing; carrying safe, pleasant-tasting water is another. Australia’s town water supplies are generally safe, but quality varies significantly between locations. Tank water, bore water, and some remote area supplies may require treatment before use.
Common Water Quality Issues
Chlorine taste is the most common complaint about Australian town water. While chlorine keeps water safe during transport and storage, it makes coffee taste terrible and can be off-putting for drinking. Simple carbon filters remove most chlorine taste and odour.
Sediment is common in older town supplies and tank water. It’s usually harmless but affects taste and appearance. Sediment filters are cheap and effective, but they need regular replacement in high-sediment areas.
Hard water (high mineral content) is common across much of Australia. It doesn’t affect safety but makes soap less effective and can leave spots on dishes and glassware. Water softening systems are complex and expensive for caravan use, so most people just accept hard water as part of the travel experience.
Filtration Options
Inline water filters integrate directly into your caravan’s plumbing system, filtering all water as it enters your taps. They’re convenient and comprehensive but require periodic cartridge changes and can reduce water pressure if they become clogged.
~$65
Portable water filters give you more flexibility but require active use. Counter-top units filter water on demand, while gravity-fed systems can filter large quantities slowly. Portable filters are ideal if you only need filtered water for drinking and cooking.
UV sterilisation systems kill bacteria and viruses without affecting water taste. They’re essential if you’re using water from uncertain sources like bores or tanks. However, they don’t remove sediment or improve taste, so they’re often combined with other filtration methods.
Maintenance and Sanitisation
Water tanks require regular maintenance to prevent bacterial growth and maintain water quality. Stagnant water in warm conditions is a breeding ground for harmful bacteria, and neglected tanks can make you seriously ill.
Regular Sanitisation
Sanitise your water system every 3-6 months or after any suspected contamination. The process involves draining your tanks completely, adding a chlorine solution, filling the system, letting it sit for several hours, then flushing everything through with fresh water.
Use unscented household bleach (sodium hypochlorite) at a rate of 1ml per litre of tank capacity. Run the chlorinated water through all taps and appliances to sanitise the entire system. The smell should be noticeable throughout the system; if not, you haven’t added enough bleach or mixed it properly.
Keep a bottle of unscented bleach specifically for tank sanitisation. Regular bleach contains additives that can leave residues in your water system.
Tank Cleaning and Inspection
Physical cleaning removes sediment and biofilm that sanitisation alone cannot eliminate. This requires accessing your tank’s interior, which is easier with some systems than others. Tanks with large inspection ports or removable lids are much easier to clean thoroughly.
Inspect tank fittings regularly for leaks or corrosion. Water leaks can cause significant damage to your caravan’s structure, and early detection saves expensive repairs. Check all connections, especially after rough road travel that can stress fittings.
Hose and Connection Maintenance
Your filling hose is often the weakest link in water system hygiene. Hoses left on the ground pick up contamination, and those stored in hot, humid conditions can develop internal bacterial growth. Use a dedicated drinking water hose and store it properly between uses.
~$85
Our Recommendations by Travel Style
The best water carrying solution depends entirely on how you travel. Here’s what we recommend for different Big Lap styles:
| Travel Style | Primary Storage | Backup/Emergency | Total Capacity |
|---|---|---|---|
| Park Hopper Most Common | 80L internal tank | 20L jerry can | 100L (2-3 days) |
| Free Camper | 120L internal tank | 40L portable containers | 160L (4-5 days) |
| Remote Explorer | 120L internal tank | 100L external + 40L emergency | 260L (7+ days) |
| Weight-Conscious | 60L internal tank | Flexible bladders as needed | Variable (1-4 days) |
Park Hoppers (1-2 nights per location)
If you’re moving frequently and usually staying in caravan parks or towns, minimal water storage works fine. Your van’s standard internal tank plus one jerry can gives you enough capacity for 2-3 days and flexibility for the occasional free camp.
Focus on water quality over quantity. A good inline filter makes more difference than extra capacity when you’re regularly accessing different town supplies.
Free Campers (3-7 nights off-grid)
Free camping requires more water storage and better management. A 120-litre internal tank plus portable backup gives you the flexibility to stay put when you find a great spot or push through to the next water source if needed.
Consider adding an external tank if your van’s internal capacity is limited. The extra complexity is worth it for the extended autonomy.
Remote Area Explorers
Remote area travel demands maximum water capacity and redundancy. You need enough water for your planned itinerary plus emergency reserves for unexpected delays or mechanical problems.
Multiple storage systems reduce single-point failure risk. If your main tank develops a leak, you still have water to get back to civilisation. Consider carrying water purification tablets as an absolute last resort.
Weight-Conscious Travellers
If you’re pushing towing limits or trying to maximise fuel economy, water weight management becomes critical. Carry minimum base capacity and supplement with flexible storage as needed.
Plan your route around reliable water sources and be prepared to fill up more frequently. This approach requires more active management but keeps your rig light and efficient.
- Most Big Lappers need 3-5 days of water storage (120-200L for two people)
- Internal tanks are best for primary storage; external tanks and portable containers work well for backup capacity
- Water weight significantly affects towing dynamics – plan tank placement carefully
- Regular sanitisation and maintenance are essential for safe water storage
- Match your water carrying system to your travel style – park hoppers need less capacity than remote area explorers
- Quality filtration improves water taste and is worth investing in regardless of your storage setup
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