The Complete Caravanners’ Guide To Carrying Water

Water is the most critical resource on any Big Lap, yet most caravanners dramatically underestimate how much they’ll need or how complex water storage becomes on extended trips. You can survive weeks without food, but just three days without water. When you’re planning months or years on the road, your water carrying capacity determines where you can camp, how long you can stay off-grid, and ultimately how much freedom your Big Lap delivers.

The challenge isn’t just carrying enough water for drinking. You need water for cooking, washing dishes, showering, cleaning your van, and filling your grey water systems. A family of four easily uses 80-120 litres per day when living comfortably. Yet most caravans roll off the lot with a single 95-litre fresh water tank.

This guide breaks down everything you need to know about water storage, from understanding different tank materials to calculating your actual water needs. We’ll cover the pros and cons of built-in tanks versus portable options, explain why tank placement matters more than capacity, and help you design a water system that matches your travel style.

How Much Water Do You Actually Need?

Most caravanners wildly underestimate their water consumption because they’ve never tracked it at home. The “8 glasses a day” rule only covers drinking water. When you’re living in your caravan full-time, water usage explodes across dozens of daily activities.

Here’s what real Big Lap water consumption looks like:

Daily Water Usage by Activity

These numbers assume you’re being water-conscious. Add another 20-30% if you want to live more comfortably with longer showers and less rationing. Factor in washing the van exterior, filling up jerry cans for generators, or dealing with spills, and you’re easily hitting 100+ litres per day for a family.

Planning Your Water Capacity

Your total water carrying capacity should cover your maximum time between reliable water sources, plus a safety buffer. Most Big Lappers find they need:

• Solo travellers: 150-200 litres for 7-10 days independence
• Couples: 250-350 litres for 5-7 days off-grid
• Families: 400-500+ litres for 4-5 days between towns

The key word is “between towns”. You’re not carrying water for month-long bush camping. You’re covering the gaps between reliable water sources while maintaining comfortable living standards.

Built-In vs Portable Water Storage

Every caravan water system is built around a choice: integrated tanks that become part of your van’s structure, or portable containers you can remove and refill separately. Each approach solves different problems.

Built-In Tank Systems

Built-in tanks mount permanently under your caravan chassis or inside storage compartments. They connect to your van’s plumbing system and fill through an external port.

Advantages:

• Large capacity without taking up interior space
• Integrated with your pump system and taps
• Lower centre of gravity improves towing stability
• Can’t be stolen or forgotten at a campsite
• No lifting heavy containers

Disadvantages:

• Must move your entire van to access water
• Harder to clean and maintain
• Expensive to repair or replace
• Can’t partially fill for weight management
• Water quality degrades if left sitting

Built-in tanks work best for caravanners who move frequently and prefer the convenience of large capacity. They’re particularly valuable for big rigs where portable containers would be difficult to manage.

Portable Container Systems

Portable systems use removable containers, typically 20-25 litre jerry cans or purpose-built water containers. You carry multiple containers and refill them as needed.

Advantages:

• Easy to clean and maintain
• Can refill containers without moving the van
• Modular capacity – add or remove containers as needed
• Easier to manage water quality
• Lower upfront cost
• Containers double as emergency backup

Disadvantages:

• Takes up valuable storage space
• Heavy lifting when full
• Higher centre of gravity affects stability
• More components to secure while travelling
• Limited by container sizes

Tank Materials: Poly vs Stainless Steel

The material your water tank is made from affects taste, durability, weight, and cost. Most caravan manufacturers offer polyethylene (plastic) tanks as standard, with stainless steel as an upgrade option.

Polyethylene (Poly) Tanks

Food-grade polyethylene is the most common caravan tank material. Modern poly tanks use UV-stabilised plastic that resists cracking and degradation.

Pros:

• Lightweight – crucial for weight-sensitive caravans
• Lower cost than stainless steel
• Won’t dent or corrode
• Easy to repair with plastic welding
• Good insulation properties

Cons:

• Can absorb odours and flavours over time
• UV degradation if not properly shaded
• More prone to algae growth in warm conditions
• Can become brittle in extreme cold
• Harder to clean thoroughly

Quality matters enormously with poly tanks. Cheap tanks crack easily and taint water. Look for tanks from reputable Australian manufacturers like Rapid Spray or TTi Tank Technology that use virgin food-grade polyethylene with UV stabilisers.

Stainless Steel Tanks

Marine-grade stainless steel (316 grade) provides the ultimate in durability and water quality, but at a significant weight and cost penalty.

Pros:

• No taste or odour absorption
• Superior hygiene – easier to sterilise
• Extremely durable – 20+ year lifespan
• Naturally antimicrobial
• Retains resale value

Cons:

• Heavy – adds 15-25kg over equivalent poly tank
• Expensive – 2-3x the cost of poly
• Can dent from impacts
• Poor insulation – water heats up faster
• Requires specialist welding for repairs

Stainless steel makes sense for caravanners who prioritise water quality and have weight capacity to spare. It’s particularly valuable in tropical conditions where bacterial growth is a concern.

Why Tank Placement Matters More Than Size

Tank placement affects your caravan’s handling, accessibility, and safety more than the tank’s capacity. Poor placement creates problems that no amount of water capacity can solve.

Chassis-Mounted Tanks

Most caravans mount water tanks under the chassis, between the axles. This location keeps weight low and doesn’t consume interior space.

Critical considerations:

• Ground clearance: Large tanks reduce clearance and are vulnerable to damage on rough roads
• Weight distribution: Heavy water affects nose weight and stability
• Protection: Tanks need stone guards and impact protection
• Drainage: Low points must have drain valves for winterising

Internal Tank Mounting

Some caravans mount tanks inside storage compartments or under seating. This protects the tank but reduces usable space and raises the centre of gravity.

Benefits:

• Better protection from impacts and weather
• Easier access for maintenance
• No ground clearance issues
• Less freezing risk in cold conditions

Drawbacks:

• Higher centre of gravity reduces stability
• Takes up valuable storage space
• Weight distribution may be less optimal
• May require removing other items to access tank

Portable Water Solutions

Portable water containers offer flexibility that built-in tanks can’t match. You can refill them without moving your caravan, clean them thoroughly, and adjust your carrying capacity based on your itinerary.

Standard Water Jerry Cans

The humble 20-litre jerry can remains a favourite among experienced Big Lappers. They’re cheap, robust, and universally available.

Jerry can advantages:

• Proven reliability – the design hasn’t changed in decades
• Easy to handle when full (20L = 20kg)
• Stackable for efficient storage
• Available everywhere across Australia
• Multiple smaller containers reduce single-point failure risk

Jerry can limitations:

• Small neck makes cleaning difficult
• No level gauge – hard to estimate contents
• Repeated lifting can strain your back
• Time-consuming to fill multiple containers

Purpose-Built Water Containers

Several manufacturers make containers designed specifically for caravan water storage, with features like level gauges, larger openings, and integrated taps.

These containers cost more than jerry cans but offer better usability. The Thetford Aqua-Tainer ~$65 includes a level gauge and wide-mouth opening that makes cleaning easy.

Flexible Water Bags

Flexible water bags store flat when empty but hold 40-100 litres when full. They’re popular with off-road tourers who need maximum capacity in minimal space.

Flexible bag pros:

• Compact storage when empty
• Large capacity options available
• Fits irregular spaces
• Lightweight construction

Flexible bag cons:

• Vulnerable to punctures
• Difficult to clean inside
• No structure when partially full
• Expensive compared to rigid containers

Keeping Your Water Fresh and Clean

Water quality deteriorates quickly in caravan conditions. Warm temperatures, sunlight exposure, and contamination during filling create perfect conditions for bacterial growth and taste problems.

Water Treatment Basics

Every caravan water system needs basic filtration and treatment to maintain water quality over time.

Inline water filters connect directly to your water system and filter all water entering your tanks. The Puretec Caravan Water Filter ~$195 removes chlorine, sediment, and improves taste without reducing water pressure significantly.

UV sterilisers kill bacteria and viruses without adding chemicals to your water. They work well for caravanners who refill from questionable sources, though they require 12V power and regular lamp replacement.

Water purification tablets provide chemical sterilisation for emergency situations. Keep a pack of Aquatabs Water Purification Tablets ~$12 as backup for contaminated water sources.

Tank Maintenance

Regular tank cleaning prevents the buildup of biofilm, sediment, and bacterial contamination that creates taste and health problems.

Monthly cleaning routine:

1. Drain tanks completely
2. Fill with cleaning solution (sodium metabisulphite or specialised caravan tank cleaner)
3. Let sit for 2-4 hours
4. Drain and flush with clean water
5. Refill with fresh water

The Puretec Caravan Tank Cleaner ~$18 breaks down biofilm and eliminates bacteria without leaving chemical residues. It’s safer and more effective than household bleach for tank sanitisation.

Our Water Storage Recommendations

Your ideal water storage setup depends on your travel style, caravan size, and tolerance for maintenance complexity. Here are our recommendations for different Big Lap scenarios.

Best Overall Setup: Hybrid System

Most successful Big Lappers end up with hybrid systems: a moderately sized built-in tank for daily use, supplemented by portable containers for extended off-grid periods.

Recommended hybrid setup:

• Built-in: 150-200L poly tank with inline filter
• Portable: 4-6 x 20L jerry cans or Aqua-Tainers
• Emergency: 2 x 10L collapsible water bags
• Treatment: Inline filter plus tank cleaning supplies

This setup gives you 240-320 litres total capacity, with the flexibility to leave portable containers behind when weight or space is critical.

Budget-Conscious Option

If you’re working with a tight budget or retrofitting an older caravan, start with portable containers and add built-in capacity later.

Premium Option

For caravanners who prioritise water quality and have weight capacity available, a stainless steel built-in tank with comprehensive filtration delivers the ultimate water experience.