True meaning behind ‘H’ on signs outside people’s houses has been shared

Joe Harker
2026-02-12T20:34:28.689Z
News

You see them everywhere and they contain some important information

Take a little walk around pretty much any town in the UK and you'll see all these 'H-signs' around the place. If you've ever wondered what they mean, then you've come to the right place.

South Yorkshire Fire and Rescue took to TikTok to explain it in a quick video, where they said 'they exist to tell firefighters where the nearest hydrant is located'.

Simple, right? Well, there’s a bit more to it.

Those yellow and black markers are crucial for emergency services because they make hydrants easy to find in a hurry. And when you’re dealing with a blazing building, every second counts.

The giant ‘H’ tells the fire brigade there’s a hydrant nearby, but the numbers on the sign are where it gets interesting.

You’ll usually spot a large number between the gaps in the ‘H’, and sometimes a smaller one as well.

The bigger number at the top shows the diameter of the water main in millimetres, so firefighters know exactly what size connection they’re dealing with. That way, they can quickly work out the pressure and flow available before hooking everything up.

So next time you see one of those ‘H’ signs, you’ll know it’s not random street furniture – it’s a vital marker that could make all the difference in an emergency.

You've probably seen these signs all over (Getty Stock Photo)

The number underneath the 'H' tells you how many metres away the hydrant is, so if it's a little bit away you'll know you're not standing directly on it.

Some of the signs even come with a little arrow pointing people in the right direction, but that's pretty rare.

Now you know what those signs mean you'll be able to find your nearest hydrant and know how big the water main is, should that ever be pertinent information in your life.

Something else the emergency services would like you to know is that you shouldn't park on the hydrants themselves, because if they have to deal with a fire it would really help if your car wasn't parked right over the access point to their nearest water source.

You'll also get in trouble for damaging or obstructing one, as well as painting over the bright yellow colours.

@southyorkshirefire
you already knew this, right? #firefightertok
♬ Sailing - yourmusic4ever💯

Brits should also leave the hydrant itself and access to the water main to the professionals, as it's illegal to use them to get water for any purpose besides firefighting unless you get permission to do so.

In other words, don't go on a hydrant hunt and then try to access the water yourself.

There are plenty of signs around the UK which are considered pretty confusing, including some of the ones on the road which drivers really ought to know better.