People have been left stunned after a TikTok video revealed what the yellow H signs on lampposts are for.

Many of us will have clocked the signs in our day-to-day life and wondered what their purpose was without seeking out an answer.

Well now a helpful TikTok from South Yorkshire Fire has revealed the significance of the little signs.

A video, posted on the fire service’s account says: “POV: You’ve walked past these small yellow signs your whole life.


@southyorkshirefire Top or bottom? #FirefighterTikTok #FireHydrant ♬ original sound - marianne

"But it was today you realised, finally, after all these years, they are there to tell firefighters where the hydrants are."

The larger number at the top of the sign indicates the size of the water main that feeds the hydrant in millimetres.

The smaller number at the bottom of the sign is the distance to the hydrant from the sign.

While some of the yellow hydrant signs will also include a direction at the very bottom of them, to show fire crews in which direction the hydrant is located.

Hydrants Direct, a company that maintains and tests privately owned fire hydrants, explained that the signs are usually the responsibility of the local authority fire and rescue services.


@southyorkshirefire What's the weirdest place you've spotted one of these signs? #hydrants #firehydrants #learnontiktok ♬ original sound - Anthony Immediato 🤎

They said: “The location of a fire hydrant is indicated by an above ground post or marker plate.

“Hydrant marker plates are rectangular yellow signs, with a large black H and a pair of numbers, usually attached to a wall, lamp post or a short concrete post.

“The two numbers on the plate show the size of the water main and the approximate distance of the hydrant from the plate. Yellow paint is sometimes used to help identify a fire hydrant cover.

“As well as marker plates, all hydrants are also shown on the digital maps available in fire engines, so that the nearest one can be found while firefighters are on their way to an incident.

“This also means that even if marker plates are missing or broken, the fire service will still be able to find them in most cases, and once reported they will be repaired in due course."