City folk might have noticed strange markings popping up along the city's roads and wonder what they are.

The yellow H's sprayed in the roads, or a yellow post and black H, are from Norfolk Fire and Rescue, marking out when a fire hydrant is near or a hydrant cover is seen on the ground.

The trial, which has proven successful so far, will hopefully keep the vital hydrants clearer for emergencies in the future.

A spokeswoman for Norfolk Fire and Rescue said: "We're required by law to highlight the location of the 22,000 fire hydrants across Norfolk.

The H marks are appearing along the road and on lamp posts around the cityThe H marks are appearing along the road and on lamp posts around the city (Image: Gary Champion)

"So we carried out an 18-month trial of using these thermoplastic markings to mark H's along the highway. 

"It's been successful and the material has remained highly visible, even in areas of heavy traffic use.

"The H markings are there in addition to the hydrant posts which also mark their locations.

READ MORE: Witnesses recall moment cartoonist died in river Wensum

"They're very useful for our crews in emergencies particularly in hours of darkness and in rural areas where the posts may not be immediately visible."

The markings are to help make people aware of the location of a fire hydrant or coverThe markings are to help make people aware of the location of a fire hydrant or cover (Image: Gary Champion)

Valves connected to the water mains underground are regularly check by the hydrant team to ensure they're ready to use in an emergency.

READ MORE: City airport hanger given green light to host weddings

Gary Champion, Green Party councillor for Sewell Ward, met one of the support team on Tuesday and said: "It's important to highlight that inconsiderate parking, which obstructs fire hydrants or prevents access for fire fighting use, place people's lives at risk. 

"So firefighters can take all reasonable measures to ensure there is an adequate supply of water access to water supplies quickly.

"So hopefully this trial will help people recognise where they are so they can leave the required 50cm each side of the hydrant and avoid any issues."

Green Party councillor Gary Champion, pictured right, with a member of the fire hydrant support unitGreen Party councillor Gary Champion, pictured right, with a member of the fire hydrant support unit (Image: Gary Champion)