Is high water pressure causing leaks inside your caravan?


It’s a common issue that we often hear/talk about; this was some conversation from around a campfire on the banks of the Barcoo River in NW Qld on this very subject.

Question by “Mr Problem”

Our caravan has one of those Shurflo INLET Mains Pressure Regulator Inlet (aka pressure regulator and non-return valve) thingy’s on the outside of our caravan which we connect to a water tap.

The first one we had was replaced at 3 years of age because it was leaking – it made a horrible mess inside the caravan.

The current one is now 3 years old and it has just started leaking (again) – but not all the time?

After consulting Google I have found that this problem is not an uncommon one but there does not appear to be a better design available and if there was it could mean a lot of work.

I have tightened up the screws probably less than 1/8 of a turn (as they are into plastic).  I reckon that there is an O ring seal that might leak if the screws are not tight especially when water pressure is high.

Perhaps the plastic body distorts over time – who knows with these things?

I’m thinking to add some stainless steel spring washers under the screw heads to stop screws moving which might help – I’m now getting desperate?

As a last resort, I might replace it with a brass non-return valve and pressure regulator mounted under the caravan as a solution but that’s going to look UGLY and TACKED ON?

Our Answer by “Mr Solution”

The Shurflo unit INLET thingy as you call it limits the operating pressure to 50 psi. They key word is INLET as guess what it’s not leaking from the outside pressure coming in, it’s actually leaking because of inside pressure building up.

The problem is caused by the additional pressure generated by the operation of the hot water system and generally only when being heated up from cold.

The Hot Water tank pressure relief valve as fitted to most caravans is specified as 150 psi which is 3 times higher than the Shurflo rating so the pressure has only one way to go and that’s into your van from the Surflo…messy eh!

Try installing a John Guest push on 12mm Non Return Valve (priced around $20.00 from most caravan spare joints (including Swift) immediately adjacent to the Shurflo unit outlet pipe.

This simple “thingy” isolates the Shurflo from the additional pressure generated by the operation of the Hot Water Unit.

The outcome for me, NO MORE LEAKS…how good is that? Pass me a beer please….


Caption – Surflo “thingy”


Water Pressure

Caption – John Guest push on 12mm Non Return Valve