What Is Hydrostatic Head

What Is Hydrostatic Head? Beginner Camper Guide

Tents can be confusing, but this post explains the important things you need to know before making your purchase. What is Hydrostatic head, is a term for water pressure that has been applied from all directions on an object or structure and not allowed to drain off naturally because of its position in relation to gravity.

Hydrostatic Head: What Does it Mean?

The term Hydrostatic Head is used to refer to the water level a tent can withstand before it collapses. If you’re looking for a polyester-based material, then this will be an important detail when buying your next shelter investment!

The hydrostatic head is a measure of how high water-resistant your tent material can be. The higher the number, the more waterproof it should be.

A Hydrostatic Head of 5000mm is equivalent to the height a column can rise before it will leak through.

The pressure exerted by a column of water is often measured in Hydrostatic Head, which measures the height (5000mm) equivalent to that of 5000mm of fluid.

The Hydrostatic Head is the measurement of how water resistant a piece of fabric will be. The higher this value, the more pressure it can withstand before leaking!

What’s a good Hydrostatic Head value for a tent?

What is Hydrostatic Head

The number of your tent doesn’t determine how dry it is. the answer to What is Hydrostatic Head includes some Factors like the shape, materials used, and orientation all affect whether or not you will be able to keep cool during a rainstorm inside your shelter.

A tent with a 10,000mm Hydrostatic Head may not keep you dry in the US. A tent made from 3000mm HH can still get wet because it is only one factor of a tent’s design and that would be very expensive to buy.

Nonetheless, the seams where the tent fabric is stitched together need to be strong. That means double stitching for durability and taped over with duct tape or sealed so that water cannot enter via any holes in either of those two sheets of material.

Zips need protection from the elements. A good tent will often cover over zippers to protect them and keep water away, but some tents go even further with a small covered porch for entrances or storm doors.

A good tent design can help keep the inside of a tent from getting wet. For instance, tents may come with waterproof and UV coating in addition to hydrostatic head material for better protection against rain or moisture entering through any opening on the outer surface.

The additional waterproof coating will help water bead off your tent and the UV coating will protect it from degrading in the sun. The trade-off is a reduced loss of color, which means you get to enjoy its original shade for longer!

It’s not just the sun that can damage your precious coatings. It turns out all sorts of everyday items are capable of causing havoc when it comes to UV and waterproofing, including oils (including natural ones like coconut oil), washing up liquid, and even bubbles!

What about the groundsheet? {What is Hydrostatic Head}

Groundsheets are usually rated for a Hydrostatic Head, which is higher than that of the main tent fabric. With groundsheets, it’s important to check and see if there are any twigs or sharp objects on the surface before pitching your tent, but don’t forget about other items such as glass!

Can I increase the Hydrostatic Head of my tent?

No, but you can improve water resistance.

Additional waterproofing sprays and seam sealers can improve the water resistance, but it also depends on how strong your fabric is. You may need to purchase an extra tarp in case of extreme downpours or heavy wind-driven rain because a lot of people get stuck with storms like this when they camp out!

The tarp we fitted to the side of the tent prevented water from seeping through our zip and helped us survive a storm. We always recommend that you take at least one tarp when camping. 


What is Hydrostatic Head? A hydrostatic Head is a metric to measure the water pressure experienced by an air column in meters of liquid. It’s not uncommon for more than one factor, such as humidity or wind direction, to influence how dry your tent will be when you’re camping out.