Cocaine in our tap water isn't the real story

It may reveal nothing to the eye, but each glass of tap water tells, on a molecular level, a remarkable story. Compounds of H20 will have spent time in the North Sea, or suspended above the Pennines. Other, rarer particles have less salubrious beginnings.

Take benzoylecgonine. This substance – found in recent tests by the Drinking Water Inspectorate (DWI) – began life as a line of cocaine. Somewhere, one of Britain’s 700,000 users snorts the drug, perhaps off a toilet seat. Temporarily, they jig. Then, after their body has broken down the alkaloid, and the high departed, they return to the toilet – this time to urinate. Filters, however, fail to expunge the benzoylecgonine from their urine, and so it arrives – the invisible legacy of a misdemeanour – in your still, silent glass.

The quantities are vanishingly small, well below the level needed to have any noticeable effect on the drinker. And because traces were found at only four sites by the DWI, it is not as if turning a tap to the left connects one directly to Colombia’s drug cartels.

Nevertheless, as some citizens will smile at the tap today, others will approach it with a little more caution. Scares are difficult to strain from the current of public discourse. Internet chatrooms still rehearse the story that quantities of oestrogen – left behind by users of the Pill – have contaminated drinking water, and contributed to a rise in the number of men developing female breast tissue. This is demonstrably false. Britain’s tap water ranks among the safest in the world. It is checked 30,000 times a year for chemical and bacterial impurities. Confusion arises, in part, because the testes of male fish have been shown to shrink as a result of high oestrogen levels in sewage effluent. Terrible, no doubt, but not the same thing as your tap water-guzzling son developing an unwanted bosom.

There are two more important stories contained within a glass of water. The first is global, and UK-based drinkers can do little about it. Despite the World Health Organisation’s claim in 2012 that it had succeeded in halving the number of people worldwide without access to safe drinking water, no such progress has been made.

A WHO report admitted last month that its guidelines had simply encouraged governments to improve pipelines – but not the water flowing through them. People receiving the same old trickle of dirty liquid, through a shining pipe, were mistakenly counted as having access to water as clean as London’s.

The second story is local, and easier to counteract. An estimated 30 per cent of water on sale in supermarkets globally comes from a tap, and only half of plastic bottles sold are recycled. That leaves the rest to fill up landfill sites, or bob about in the ocean. The enviornmentalists’ lament is so familiar it has lost some of its punch: nobody can live day-to-day with the Great Pacific Garbage Patch swirling in the back of their mind. Yet the mark-up between tap water and bottled is extraordinary, the equivalent of paying £1,500 for a pint. If you’re looking for a scare story in our water supply, there’s one to be found, but it’s got nothing to do with micro-traces of cocaine.