The Complete Caravanners’ Guide To Carrying Water

Water is arguably your most critical resource on the road. You can survive weeks without food, but only days without water. For caravanners, this creates a fundamental challenge: how much water should you carry, what type of tanks work best, and how do you balance capacity against weight?

The water carrying landscape has evolved dramatically in recent years. Traditional single-tank setups are giving way to multiple tank systems, grey water management has become more sophisticated, and new materials offer better durability at lighter weights. Understanding your options before you buy can save you thousands in retrofits later.

Tank Types: Poly vs Stainless Steel

Your tank material choice affects everything: taste, weight, durability, and cost. The two dominant materials serve different priorities.

Polyethylene (Poly) Tanks

Poly tanks dominate the caravan market for good reason. They’re significantly lighter than steel alternatives, won’t corrode, and cost substantially less. Quality varies enormously though. Cheap poly tanks develop stress cracks around fittings, while premium options like Aussie Tanks ~$180-450 use UV-stabilised polyethylene that lasts decades.

The main drawbacks are thermal expansion (you’ll hear creaking on hot days) and potential plastic taste if the tank sits in direct sunlight. Most quality manufacturers now include UV inhibitors to prevent degradation.

Stainless Steel Tanks

Stainless steel eliminates taste issues and offers superior durability, but you’ll pay significantly more in both purchase price and weight penalty. A 100L stainless tank weighs roughly 15kg empty compared to 8kg for equivalent poly.

Premium manufacturers like Tekcraft Engineering ~$650-1200 build custom stainless tanks that last indefinitely. The investment makes sense if you’re planning extended off-grid travel where tank failure could be dangerous.

How Much Water Do You Actually Need?

Water planning involves three separate calculations: fresh water consumption, grey water storage, and reserve capacity. Getting this wrong leads to either constant anxiety about running dry or hauling excessive weight.

Daily Fresh Water Usage

Conservative planning assumes 20-25L per person per day for drinking, cooking, and basic hygiene. This covers morning coffee, meal preparation, teeth brushing, and limited washing. Couples typically use 45-50L daily, families of four around 80-100L.

These figures assume disciplined water use. If you’re accustomed to long showers and don’t want to change habits, double these estimates. Many Big Lappers start conservative and add capacity later based on real-world usage patterns.

Grey Water Considerations

Grey water (from sinks and showers) typically equals 60-70% of fresh water consumption. A couple using 50L of fresh water daily generates roughly 30-35L of grey water. This matters because many caravan parks now require grey water containment.

Reserve and Emergency Planning

Smart caravanners carry 2-3 days of emergency water beyond their planned consumption. This buffer handles unexpected delays, contaminated water sources, or equipment failures. For remote travel, consider carrying additional water in portable containers rather than oversizing fixed tanks.

Single Tank vs Multiple Tank Systems

Tank configuration affects weight distribution, redundancy, and flexibility. Each approach serves different travel styles and caravan layouts.

Single Large Tank Systems

Single tank systems simplify plumbing, reduce potential leak points, and cost less initially. A single 120L tank serves most couples adequately and keeps the water system straightforward. Weight sits in one location, which can help or hurt depending on your van’s balance requirements.

The downside is putting all water eggs in one basket. Tank failure means losing your entire fresh water supply. Single tanks also make it harder to optimise weight distribution across the caravan chassis.

Multiple Tank Configurations

Multiple smaller tanks offer superior redundancy and weight distribution flexibility. Two 60L tanks weigh the same as one 120L tank but can be positioned to optimise chassis loading. Tank failure only costs half your water supply.

The trade-off is complexity. More tanks mean more fittings, more potential leak points, and higher installation costs. You’ll also need either multiple tank gauges or a switching system to monitor levels.

Modular Water Systems

Some manufacturers now offer modular systems where standardised tanks connect via quick-release couplings. Adventure Kings ~$150 per 40L module pioneered this approach, allowing you to add or remove capacity based on trip requirements.

Modular systems excel for varying trip types. Carry minimal water for caravan park tours, add modules for off-grid adventures. The flexibility comes at a weight penalty due to multiple tank walls and fittings.

Grey Water Management Options

Grey water handling has become mandatory rather than optional. Understanding your options helps avoid costly retrofits and ensures compliance with changing regulations.

Fixed Grey Water Tanks

Fixed grey water tanks mount permanently under the caravan chassis. Sizes typically range from 40L to 100L, with 60-80L being most common for couples. Quality tanks include drain valves and inspection ports for maintenance.

Fixed tanks offer the cleanest installation and highest capacity, but add permanent weight and complexity to your undercarriage. They also require dedicated dump points rather than simple ground disposal.

Portable Grey Water Solutions

Portable grey water tanks offer flexibility at the cost of convenience. Options range from simple 20L containers to wheeled 100L units with electric pumps. The Camec Portable Grey Water Tank ~$190 includes wheels and a tow handle for easy transport to dump points.

Portable solutions work well if you primarily stay in caravan parks with easy dump access. They become tiresome for extended off-grid camping where you’re constantly emptying containers.

Grey Water Treatment Systems

Advanced grey water systems filter and treat water for reuse in toilet flushing or external washing. These systems cost significantly more but can extend water supplies for extended off-grid stays.

Treatment systems only make financial sense for serious off-grid travellers. The complexity and maintenance requirements outweigh benefits for most Big Lappers who regularly access fresh water supplies.

Pumps and Plumbing Considerations

Your water pump and plumbing design affects system reliability, water pressure, and power consumption. Choosing components that match your usage patterns prevents frustration and premature failures.

Pump Selection

Most caravans ship with basic diaphragm pumps that cycle constantly to maintain pressure. These pumps work adequately but consume power continuously and create noise. Upgrading to an accumulator tank system reduces cycling and improves shower pressure.

The Shurflo Trail King 7 ~$165 represents the sweet spot for most installations: reliable, quiet, and sufficient flow for typical caravan plumbing. Pair it with a 2L accumulator tank to minimise cycling.

Plumbing Materials

Most caravans use PEX (cross-linked polyethylene) plumbing for flexibility and freeze resistance. Quality varies significantly between manufacturers. Premium systems use colour-coded lines (red for hot, blue for cold) with proper support brackets every 600mm.

Avoid systems using garden hose or cheap plastic fittings. These create taste issues and fail under pressure cycling. Invest in quality brass or stainless steel fittings at connection points.

Hot Water Integration

Hot water systems complicate plumbing but dramatically improve livability. Most caravanners choose between instantaneous gas units and traditional storage systems. Your water carrying capacity affects which option works best.

Storage hot water systems use tank capacity but provide consistent temperature and pressure. Instantaneous systems preserve tank capacity but require higher water pressure and flow rates to operate effectively.

Weight Distribution and Mounting

Water weighs 1kg per litre, making tank placement critical for caravan handling and legal weight compliance. Poor placement creates dangerous handling characteristics and potentially illegal axle loads.

Chassis Mounting Considerations

Water tanks mount either between chassis rails or externally on custom brackets. Between-rail mounting protects tanks from road debris but limits size options. External mounting allows larger capacity but exposes tanks to damage.

Professional installation ensures proper load distribution and secure mounting. DIY installations often overlook stress concentration points or fail to account for dynamic loads during travel.

Weight Distribution Impact

Tank placement affects both tow ball weight and individual axle loads. Tanks positioned ahead of the axles increase ball weight, while rear-mounted tanks can create dangerous weight transfer during braking.

The ideal position is over or slightly behind the axle group, but this conflicts with grey water tank placement and other equipment. Most installations represent compromises between ideal weight distribution and practical accessibility.

Our Recommendations by Travel Style

Your optimal water system depends on travel style, budget, and technical comfort level. These recommendations reflect real-world experience across different Big Lapper profiles.

Budget-Conscious Starters

New caravanners benefit from starting simple and upgrading based on experience. A single quality poly tank with portable grey water handling costs under $500 installed and handles most scenarios. Add capacity later once you understand your actual usage patterns.

Serious Off-Grid Systems

Extended off-grid travel demands redundancy and large capacity. Multiple tank systems with quality pumps, monitoring, and grey water treatment justify their complexity for remote adventures. Budget $2000-3000 for comprehensive systems.

Consider modular approaches that allow capacity adjustment based on trip requirements. Fixed high-capacity systems excel for consistent off-grid travel but penalise shorter trips with unnecessary weight.

Full-Timer Recommendations

Full-time caravan living requires robust systems that handle daily use without constant maintenance. Invest in quality components initially rather than upgrading incrementally. Stainless steel tanks, quality pumps, and comprehensive monitoring pay dividends over years of use.