Thread by @stukhan

Have you ever wondered what these little "H", "HP", "HR" and "SV" signs, nailed or adhered to NSW telegraph poles or streetsign poles, mean? If so, read on...

All of the signs with a "H" are markers for the location of a subsurface fire hydrant. The "P" indicates that the hydrant is under the "pathway" and the "R" indicates that it's under the "road". The green colour indicates that the hydrant is on the opposite side of the road.

Sometimes there are numbers between the letters. The top number is the distance (in metres) from the marker to the hydrant. The bottom number is the size (in millimetres) of the water main. The markers also generally face in the direction to the hydrant.

So once you see the marker, you should be able to find the location of the hydrant. It's under a cast iron cover, on the road or footpath. Finding them can be a fun walking-to-school game 🙂. Sometimes they're painted yellow to make it easier.

Increasingly, you'll also see these little blue reflective markers on the road. They also indicate the location of an adjacent fire hydrant. They can be easier for fire services to find in the night.

Finally, "SV" stands for "sluice valve", which is an on-off tap fitted to a water pipe. The water utility can use it to isolate sections of the water supply for maintenance or to shut of major leaks. Again the numbers indicate the distance (9m) and size of the water main (100mm).

So now you know.

Actually, I described the green ones a bit wrong. The green ones basically mean “you’re getting warmer, but you’re not quite there”. Keep looking for a red one (hint: try the other side of the pole!).

To use the hydrants, the fire services need to attach a ‘hydrant riser’ and connected their hoses to it. Community members should ensure that they’re never obscured and never park a car over a hydrant.