The crucial role of yellow H symbols on lampposts that many don't realise

The yellow H symbols can be found on lampposts, drain covers and street markers and South Yorkshire Fire and Rescue has shared a video explaining what they mean

Daily passersby often overlook them, but their significance cannot be understated. South Yorkshire Fire and Rescue has taken to social media to explain the mystery behind the yellow H symbols seen on lampposts, enlightening the public as to their crucial role.

In an intriguing TikTok video, which has now attracted over one million views, they expressed: "Point of view: You've walked past these small yellow signs your whole life but it was today you realised, finally, after all these years, they are there to tell firefighters where the hydrants are."

The familiar symbols, regularly spotted on drain covers and street markers, feature two numerals inscribed within a larger H. The upper figure denotes the diameter of the water main connected to the hydrant, measured in millimetres, while the lower indicates how many metres away the hydrant is from the sign.

Occasionally, these signs also incorporate an arrow at the base pointing towards the hydrant's location. Cambridgeshire Fire and Rescue Service also issued a statement, advising: "Seen one of these yellow H signs in the street? These indicate that a hydrant is nearby. We use these to access the water main when we need to refill our engines or access an additional water supply. We may need to access a hydrant at any time, so please be sure to keep them clear."

Commenting on the TikTok video, one user expressed their shock: "I only learned the other week that they don't carry all of the water on the trucks - so I'm doomed.", reports the Mirror.

Another revealed an indifferent attitude stating, "It's nothing to do with me so I just walk on by. What do I need to know for? " and a third person confessed past confusion: "I used to think it was H for helicopter landing."

One more user highlighted a gap in education: "I had no idea and I am a teen I think we need to be educated on the real world as well as things like maths and science."

However, some users were already familiar with the information, as one mentioned, "I was taught that in primary school."

Finally, another user reminisced, "My mum has one in her garden. I used to love it when the fire engine used to come and fill up."