Featured Image for Techly Explains: Do I really need to run taps for 30 seconds before drinking?
Techly Explains

Techly Explains: Do I really need to run taps for 30 seconds before drinking?

Concerns over lead in Australia’s water supply have re-emerged, causing plenty of hype, clickbait and fear-inducing articles doing the rounds.

Well, we’re here to cut through the noise and give you a clear-cut round-up of what the experts are saying in response to these concerns.

You know, the people who actually know what they’re talking about (we hope).

More specifically, we’ll be discussing expert responses to the advice issued by enHealth in July of this year, which stated that we should be “flushing cold water taps used for drinking and cooking for about 30 seconds first thing in the morning to draw fresh water through the tap.”

Advice that has been met with a measure of, let’s say, gentle hysteria.

Firstly, we used the word ‘re-emerged’ earlier, because these issues have been aired before. Dr Paul Harvey, environmental scientist and chemist and an adjunct Fellow at Macquarie University, says concerning this: “The latest advice to flush taps for 30 seconds isn’t new, in fact it has been around for a long time. It is only now that it has been re-issued that it has received some attention.”

In fact, it took four months for this ‘re-issued’ advice to come to the public’s attention.

“Regardless, it takes us back to the source of lead in the drinking water, which is the lead-brass plumbing,” Dr Harvey continues.

This is a point that most of the experts agree on – that while lead concentration in water supplied by Australian utilities is very low, the biggest threat is posed by old household plumbing systems – many of which contain lead in their brass fittings.

Stuart Khan, professor of Civil and Environmental Engineering at the University of New South Wales, says: “Elevated blood lead levels are rarely found to be related to lead exposure from drinking water in Australia and there is currently no evidence of adverse effects on human health from the consumption of lead in drinking water in Australia.”

“However, this doesn’t correct the legacy problem of older plumbing systems in older households and buildings. In those cases, the recommendation to flush water before use is appropriate.”

Khan goes on to express that he believes the biggest issue relates to contamination in school plumbing systems. When students return to school after long holiday breaks, “there is potential for water to have sat stagnating, with warm summer temperatures, in the school plumbing system” – causing lead to leach from the pipes into the drinking water.

“Such a scenario is all the more significant when we consider that many of the risks around which lead exposure is controlled are considered to be greatest for children, compared to adults,” Khan continues.

Running tap

The same report that created a stir with its 30-second-morning-flush warning also issued advice that relates directly to Khan’s concerns:

“Householders can proactively reduce their potential exposure to lead in drinking water through flushing cold water taps used for drinking and cooking for about 2 to 3 minutes after long periods of non-use, such as return from holidays.”

Ironically, this somewhat over-looked suggestion is perhaps the most important of the two. Khan is certainly onto something when he urges state governments to develop water quality management plans.

This issue is backed up by another expert, Professor Michael Cortie – leader of the Physics Discipline Team in the School of Mathematical and Physical Sciences at University of Technology, Sydney – who also believes that flushing a system that has stood stagnant for several weeks or longer is certainly advisable.

However, he debunks the need to run your tap for 30 seconds every morning.

“Once a cold water tap is in normal daily use this need disappears because it takes an excess of several days for metal ions to build up in stagnant water,” he says.

According to Cortie, the advice issued by enHealth is “more a matter of principle rather than actually related to any specific health concern”.

Wisely, The Australian Building Codes Board (ABCB) have been seeking independent reviews of these issues before forming a response plan. A plan that, according to Professor Anas Ghadouani – Professor of Environmental Engineering at The University of Western Australia – is “urgently needed”.

Ghadouani believes that “there is no safe level for lead exposure”, but makes no comment on the usefulness of flushing our taps each morning.

Ultimately, the evidence seems to take the stance that the 30-second flush should be considered as more of a friendly precaution rather than a do-it-or-die rule. However, these concerns have necessarily pointed us towards more pressing lead-contamination issues, such as what we are doing to safeguard schools.

In the meantime, we will keep drinking our filtered water, probably flush our taps every second day, and hope for the best!

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