I called out an engineer from Thames Water as I need to locate the main stop valve for our water supply. He arrived this afternoon and we both searched in vain for signs of the pipework. we could find the neighbour's but not our own.

He said he'd need to get some equipment from the van to check the location of the pipe. I excused myself to go get a jacket as there was a cold wind blowing. What I saw when I stepped back outside the house left me totally flabbergasted; in each hand he held a dowsing rod!

"Is this really the technology you use?" I endeavoured to say the word "technology" without any hint of sarcasm. He reassured me that this is indeed how he does it.

The engineer demonstrated how the rods deflected over the neighbour's pipes and then marked the point at which the rods responded to my property's buried pipe:

He confirmed that this was the most straightforward method available to find the hidden pipes. A work crew will now come to dig up the pavement. If they don't locate the pipe at the designated spot the workmen will resort to using a piece of equipment which will make a tapping sound on the domestic pipework. Then they will scan the pavement with an audio amplifier to determine the point at which the tapping is loudest. 

The Thames Water employee gave me a chance to test out my own skills with the dowsing rods. I walked 20 meters past a couple of properties but the rods stubbornly refused to turn even when ever I passed the stop valve covers of our neighbours. He seemed surprised. I was not; I'm a sceptic.

Was he having me on or is he one of the small band of Thames Water employees who choose low tech apparatus?