If you’re hauling water regularly, your trailer size choice matters more than you might think. Water is heavy, and it moves. Misjudging tank capacity or weight limits can affect everything from trailer safety to performance on the road. Before you load up with 500 or 1,000 litres of water, here’s what you need to know about hauling water trailer size and why it matters.

 

Why Water Weight Matters

Water weighs about 1 kg per litre. That means a 500L tank adds around 500 kg to your load. A 1,000L tank adds a tonne. And that’s just the water. Your trailer also needs to carry the tank itself, the frame, hose reels, pumps, and possibly a hot water pressure washer. Combined, this can easily push your total trailer weight into the dual-axle category.

If you’re using a setup like a hot water pressure washer trailer, make sure you factor in both the weight of the water and the weight of your equipment.

 

Does Hauling Water Require a Larger Trailer?

Does hauling water require a larger trailer? In most cases, yes. A single-axle trailer might be enough for a small tank under 400L, but anything more starts to push the limits. If you’re planning to haul water for cleaning, farming or remote work, you’ll likely need a dual-axle trailer with a higher Gross Vehicle Weight Rating (GVWR).

Choosing a larger trailer helps spread the weight more evenly, improves towing stability, and keeps you compliant with local road regulations. If you’re also adding a generator, toolbox or pressure washer, a larger trailer gives you the flexibility to position items properly without overloading the drawbar or axles.

 

Trailer GVWR for Water Hauling

Trailer GVWR for water hauling is critical to get right. GVWR is the maximum total weight your trailer can safely handle. This includes the trailer’s own weight plus everything you load onto it.

For water hauling trailers, consider the following rough guidelines:

 

  • Up to 400L tank: Single-axle trailer with minimum 750kg GVWR
  • 400L to 800L tank: Dual-axle trailer with 1,500kg to 2,000kg GVWR
  • 1,000L+ tank: Heavy-duty dual-axle trailer with 2,500kg or more GVWR

 

Your trailer must also be compatible with your towing vehicle. Check your car or ute’s towing capacity before settling on a trailer size.

 

Balancing Load and Weight Distribution

Water tanks add a lot of central weight. To avoid sway or stress on the drawbar, tanks should be positioned directly over or just forward of the axles. This gives the trailer better balance and helps stop the load from shifting during transport.

If you’re using hose reels too, think about their placement. It’s a good idea to read up on: is it safe to stack hose reels on a pressure washing trailer to avoid uneven loads.

 

Planning for a Full Setup

If your water tank is part of a larger cleaning or work setup, such as a trailer with a hot water pressure washer, you’ll need to factor in additional space and mounting hardware. Look at our advice on hot water pressure washer trailer setup to understand what kind of trailer will suit you best.

 

Ready to Upgrade Your Setup?

Water hauling impacts your trailer size more than you might expect. Between water weight, added equipment and road safety, choosing the right size can make the difference between a reliable rig and a breakdown waiting to happen. Don’t underestimate the planning. If you’re unsure, it’s safer to go bigger.

Need help choosing a trailer that can handle your full load? Coastmac has a range of high-quality trailers designed for real work in tough Aussie conditions.