Caravan Water Tank Sizes & Dimensions 2026

Getting your caravan water tank sizes and dimensions right can be the difference between a cracking Big Lap and a trip cut short by a dry jerry can at a free camp. Water is heavy, under-chassis space is tight and every extra litre eats into your payload.

Caravan water tanks in 2026 come in 4 common capacity ranges:

1. Compact fresh water tanks (40 to 55 litres)
2. Mid-size fresh water tanks (59 to 82 litres)
3. Large fresh water tanks (90 to 110 litres)
4. Grey water and portable waste tanks (23 to 110 litres)

There are 4 common caravan water tank shapes and configurations:

1. Slimline rectangular tanks designed for under-floor mounting
2. Rounded-corner roto-moulded tanks for cupboard or low-floor installs
3. Modular universal tanks that can be networked together via threaded fittings
4. Portable wheeled roll tanks for free camping and waste removal

Measuring your available bay and checking how much weight your ATM can safely carry is essential before you commit to a new tank. This guide covers the capacities, footprints and shapes you will find across the Australian caravan market in 2026.

1. Compact Caravan Water Tank Sizes & Dimensions (40 to 55 Litres)

Compact tanks in the 40 to 55 litre range suit campervans, pop-tops, camper trailers and smaller single-axle caravans where space and payload are both at a premium. They are a favourite for weekend getaways around the Victorian high country or short coastal runs where you do not need days of off-grid water.

Most are blow-moulded from food-grade high-density polyethylene (HDPE), which is non-toxic and suitable for drinking water.

• Length: 700mm to 1010mm
• Width: 260mm to 380mm
• Height (depth): 175mm to 230mm
• Capacity: 43L to 55L
• Empty weight: approximately 2.85kg to 4kg
• Filled weight: approximately 46kg to 59kg (water adds 1kg per litre)

A 43L modular tank sits at around 860mm x 260mm x 220mm, making it one of the slimmest options for narrow chassis bays.

A 50L universal tank measures roughly 700mm x 380mm x 210mm and weighs just 2.85kg empty.

A 55L roto-moulded camper tank comes in at 760mm x 350mm x 230mm and can be mounted vertically or horizontally.

2. Mid-Size Caravan Water Tank Sizes & Dimensions (59 to 82 Litres)

Mid-size tanks between 59 and 82 litres are the workhorse of the Australian caravan scene. They suit standard single and tandem-axle vans used for two-up touring, caravan park stays and longer weekends away.

This range is also the sweet spot for Grey Nomads who want a solid fresh water reserve without demanding a heavier towing vehicle. You will typically find these in a slim under-floor profile with built-in baffles to reduce slosh.

• Length: 700mm to 1220mm
• Width: 400mm to 530mm
• Height (depth): 170mm to 240mm
• Capacity: 59L to 82L
• Empty weight: approximately 4kg to 6kg
• Filled weight: approximately 63kg to 88kg

A common 59L tank measures 865mm x 490mm x 190mm and is used by many Australian caravan manufacturers as a standard fitment.

An 82L tank stretches to 1220mm x 490mm x 190mm, offering nearly 50% more capacity with only an extra 355mm of length.

AL-KO's Australian-made 62L option (990mm x 490mm x 170mm, 5kg empty) features a double baffle design and bracket retention moulded into the shell.

3. Large Caravan Water Tank Sizes & Dimensions (90 to 110 Litres)

Large tanks between 90 and 110 litres are built for serious touring, full-time Big Lap travellers, families and anyone planning extended free camping through the outback or tropical north Queensland.

Many modern tandem-axle caravans run two or three of these in parallel, which is how you get manufacturer-quoted capacities of 180 to 240 litres on off-road vans. The trade-off is real weight, so pay close attention to your caravan's ATM, payload and tow vehicle rating.

• Length: 1170mm to 1270mm
• Width: 400mm to 650mm
• Height (depth): 180mm to 220mm
• Capacity: 90L to 110L
• Empty weight: approximately 6kg to 10kg
• Filled weight: approximately 96kg to 120kg

A 95L tank typically measures 1170mm x 500mm x 220mm and weighs around 6kg empty.

The Jayco-spec 90L tank runs slightly longer at 1270mm x 400mm x 210mm, showing how manufacturers shape the footprint to suit their chassis.

At the top of the range, a 110L tank comes in at 1200mm x 650mm x 180mm and can be configured as fresh or grey water.

4. Grey Water & Portable Caravan Water Tank Sizes & Dimensions

Grey water tanks catch waste from your sink and shower so you are not dumping soapy water on the ground at free camps. Many of the fresh water tanks listed above can be repurposed as grey tanks using the right fitting kit, but there are also dedicated modular and portable options.

Portable wheeled roll tanks are a favourite for travellers who want self-contained status without a permanent under-floor install.

Under-Floor Grey & Dual-Purpose Tanks

These are typically the same slimline tanks used for fresh water, set up with grey water fittings.

Common sizes run from

1. 43L (860mm x 260mm x 220mm)
2. 110L (1200mm x 650mm x 180mm)
3. 50L universal modular tank (700mm x 380mm x 210mm, 2.85kg empty
4. 95L dual-purpose tank (1170mm x 500mm x 220mm)

Portable Wheeled Roll Tanks

Portable roll tanks come with wheels, a handle and a total-discharge cap so you can wheel waste to a dump point.

Common sizes include:

1. 23 litre units at around 500mm x 330mm x 250mm (roughly 3kg empty).
2. 40 litre units at around 410mm x 810mm x 200mm (roughly 5kg empty).

These store in the external locker or under the awning and are compact enough to fit through a standard caravan door.

Additional Caravan Water Tank Considerations

1. Payload impact:

Water weighs 1kg per litre. The Caravan Industry Association of Australia recommends a minimum payload of 300kg for single-axle and 400kg for tandem-axle caravans. A full 95L tank adds around 101kg (95kg water plus 6kg tank), so always budget water as part of your payload, not on top of it.

2. Tare Mass and ATM

Your caravan's Tare Mass is measured with empty tanks, which means filling them counts directly against your payload allowance and your ATM ceiling. Do the maths before you plan a remote run.

3. Under-floor clearance

Slimline tanks are typically 170mm to 240mm deep. Check the gap between your chassis rails and the ground, and leave room for mounting brackets, straps and breather clearance.

4. Ventilation and breathers

Most roto-moulded tanks require a small breather hole (around 5mm) or a dedicated breather fitting so the tank can draw air as it empties. Without it, you will get airlock and sluggish flow at the tap.

5. Material and food safety

For fresh water, only use tanks made from food-contact approved, non-toxic high-density polyethylene. Australian-made tanks from Camec, AL-KO and Roto Millard meet Australian food safety standards.

Top 5 Tips for How to Choose Caravan Water Tank Size and Style

Picking the right tank is a balance of how you travel, what your rig can legally carry and what will physically fit.

1. Work backwards from your payload
   Check your caravan's compliance plate for Tare Mass and ATM. Subtract one from the other and you have your usable payload. Allocate water last rather than first, because gas, bedding, tools and food fill up that number faster than most people expect.
2. Match capacity to your trip style
   A weekend caravan park trip runs comfortably on 40 to 60 litres. A week of free camping for two people usually needs 90 to 110 litres. Long remote touring is where dual or triple tank setups earn their keep.
3. Measure the mounting bay twice
   Record the length, width and available height under your van in millimetres, allowing for chassis rails, brake lines and brackets. Compare against the tank's stated footprint before you buy.
4. Think about weight distribution
   Heavy tanks behind the axle can push up ball weight and upset towing stability. Where possible, mount fresh water tanks close to or slightly forward of the axle group so the van stays balanced.
5. Plan for grey water if you free camp
   More Australian councils and national parks require self-contained rigs. A dedicated grey water tank or portable roll tank keeps you compliant. Factor its footprint and weight into the same payload calculations as your fresh tank.

Whether you are outfitting a new off-road van or upgrading the tanks on a long-serving tourer, matching capacity to your payload and bay dimensions is key. Browse the full range of caravan water tanks at CARAC, or check out the matching water tank fittings and accessories to complete your install.