If you’ve ever connected your van to a water supply only to find the pressure barely strong enough to fill a kettle—or worse, no flow at all—you’re not alone. Caravan mains pressure issues are one of the most common complaints we hear at the Adelaide RV Service Centre. Fortunately, there’s often a simple explanation—and a few easy fixes.

In this blog, we’ll walk you through the key causes of mains pressure problems in caravans, how the pressure limiting valve works, and what to do if your pump starts back feeding water.

What Is a Pressure Limiting Valve?

A pressure limiting valve is a vital part of your caravan’s water system. Its job? To reduce the incoming caravan mains pressure from the external tap, keeping it at a safe and consistent 350 KPA to avoid damaging your internal plumbing.

Most valves also contain a non-return valve (or one-way valve), which prevents water from flowing backwards—particularly when you’re using your tank and pump water off-grid.

You’ll typically find this valve near the front A-frame of your caravan, right next to the mains water connection. In some van models, it’s located further back on the driver’s side, behind the rear wheel.

Low Caravan Mains Pressure? This Could Be Why

One of the telltale signs of a faulty pressure limiting valve is low water pressure from your taps when connected to mains—sometimes just a trickle, or nothing at all.

So what’s happening?

It usually starts at the campground tap. When turned on, these taps often spit out grit, dirt, and other debris. If this debris flows directly into your caravan’s system, it can jam the spring mechanism inside the pressure limiting valve, stopping water from passing through.

Once jammed, the valve might block the water completely or only allow a slow dribble through. Not ideal when you’re trying to enjoy a hot shower or wash up after dinner.

Can You Unblock It?

Technically, yes. If you’re stuck at a caravan park and need a quick fix, you can take apart the valve, clear out the spring, and reassemble it. This can get the water flowing again temporarily.

However, these are short-term fixes at best. Once a valve has jammed once, it’s likely to happen again—often sooner rather than later.

For a permanent solution, we recommend replacing the faulty valve with a high-quality, Australian-made pressure limiting valve.

What Happens When the One-Way Valve Fails?

If the non-return valve inside your pressure fitting fails, your caravan pump may start pushing water backwards through the mains inlet. This causes water to flow straight out of your tap or hose connection, leading to water loss—especially if you’re free camping.

What to Do:

• If you’re on mains water at a caravan park: The pressure from the external tap will usually prevent back flow, so you might not notice the issue immediately.

• If you’re bush camping and using your pump: You’ll need to block off the mains inlet to keep the water in and let your pump build up pressure properly.

Simple DIY Fix for Bush Camping

If you find yourself off-grid and your one-way valve has failed, here’s a clever workaround:

• Grab a blanking cap or tap from Bunnings.

• No cap? No worries. Unscrew your garden hose fitting, remove the rubber washer, and insert a 10-cent coin.

• Screw it back on, and you’ve created a makeshift seal to stop back flow and let your pump function as it should.

This trick helps you stay water-efficient when you’re far from a service centre.

When to Replace the Valve

If you’re dealing with inconsistent caravan mains pressure or water back feeding through your A-frame tap, it’s time to replace the valve. Just make sure you buy one that includes both the pressure regulator and the non-return valve.

Some DIYers mistakenly buy a standard pressure reducer without the one-way function—only to discover their pump water is escaping through the mains outlet. It’s a small detail, but it makes a big difference.

Final Thoughts

Don’t let a small part ruin your trip. Whether you’re chasing steady caravan mains pressure or trying to avoid leaks when using your pump, the pressure limiting valve plays a huge role in keeping your water system running smoothly.

If you’re unsure what part you need—or you’d rather not get your hands dirty—swing by the Adelaide RV Service Centre. Our team is always happy to help get you Adventure Ready again.

Want more quick fixes and caravan tips? Stay tuned to our 5 Minute Fix series and follow us on socials for more expert advice on the go.