What does tent waterproof levels mean?

what does the waterproof levels on a tent mean

Tents are an essential part of any outdoor adventure. They’re also one of the most expensive items in your gear bag. So, how do you choose a good tent for your next trip to keep you and your family dry?

You’ll find different waterproofing levels on tents. This means that some tents are more resistant to moisture than others. If you’re planning on spending a lot of time outdoors, you’ll want to ensure that your tent has enough protection against the elements. What do the different waterproofing levels on a tent mean?

A tent’s fabric waterproofing is measured by a Hydrostatic Head (HH), the pressure a fabric can endure before water leakage. The HH ranges from 1,000mm to 10,000mm; the higher, the more waterproof fabric. 1,000mm is the minimum legal requirement in the UK, but most tents start from 2,000mm. Groundsheets have a higher HH rating from 3,000mm due to the constant contact with the ground and footfall.

What does Hydrostatic Head (HH) mean on a tent?

It is a method that manufacturers use for confirming a material’s resistance to water seepage. It does not just apply to tents but also to clothing, umbrellas, and other water-resistant materials.

How is a hydrostatic head test carried out?

The test is carried out by testing a sample of fabric clamped to a clear cylinder. Water is then gradually poured into the cylinder. 

For example, if the HH rating of 1,000mm means that the cylinder will hold 1,000mm of water pressure before it leaks through the fabric. At the point of seepage, that is how the HH rate is determined.

The hydrostatic head test does not take into account heavy rain driven by wind.

Why are groundsheets more waterproof than tents?

Groundsheets have a higher HH level than the regular tent fabric because of the continuous contact with the ground. Plus, the groundsheet must be tougher with the occupants’ constant movement from walking, and sitting.

Normally a ground sheet will start from 3000mm HH rating.

Can the waterproofing on a tent deteriorate?

Over time, the tent’s waterproofing will fade due to usage, weather conditions, mud, dirt, and lack of tent maintenance. Water will be absorbed by the fabric rather than running off the tent.

Tents need to be periodically reproofed using a waterproofing spray to restore water repellent whilst remaining a breathable fabric.

How often do you need to waterproof your tent & awnings?

Waterproofing your tent frequency does depend on the number of camping trips per year and weather conditions such as heavy rain and direct sunlight. These will all have an effect on the state of your tent.

If camping 2-3 weeks per year, you must reproof your tent or awning every couple of years.

Many people will not do this; they often only consider applying a waterproofing repellent when it leaks or purchasing a new tent.

When should you check how waterproof your tent is?

Pitch your tent in your back garden on a dry summer day at the start of the camping season. Test how waterproof your tent is by gently spraying water from a hose.

Don’t assume that the weather will be great and it does not matter. The UK often has rain, and although the forecast was great for our camping trip, we did have a hurricane.

How to check for water leaks

  • Does the water form water droplets on your tent, like after you have cleaned and polished your car
  • Check inside of your tent for water seepage
  • Check all seams to see if these are letting in water
  • Check the groundsheet as well, including the seams, if it is a sewn-in groundsheet
  • Toggles and ties that are stitched into your tent check for a leak
  • Zip door openings 
  • EHU cable entry make sure it is sealed
  • Fly sheets and skirts

What is the recommended waterproof rating for the UK?

It is illegal for the HH level to be under 1,000mm to camp in the UK, but most tents start from 2000mm.

For British weather, 2,000 – 3000mm is suitable for typical British weather. 2000 is ideal for warmer weather, and it does state for heavy rain. 

Our tent was 2000mm, and it leaked, but it did rain all night, and we did find ourselves camping in the middle of a hurricane. So for us, our 2000mm tent will only be for short stopover camp trips if the weather forecast looks good.

Waterproofing rating vs seasons

1000mm HH – a legal requirement of waterproofing tents in the UK – suitable for very milk basic weather such as mini light showers.

1500mm HH – Summer tents that will cope with light showers. With longer exposure to rain, they do tend to leak.

2000mm HH – Season 3 tents that can cope with heavy rainfall and wind,

3000mm plus HH – normally expenditure tents and can cope with heavy downpours, gale-force wind


I'm a single parent who loves pitching a tent and exploring the countryside at any opportunity. I am working with a glamping pod company and helping them to set up a family campsite in East Riding Yorkshire.

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