In July 2018, the Environmental Health Standing Committee (enHealth) issued a statement about the risk of lead in drinking water from plumbing materials. The advice included:
using only water from cold taps for drinking and cooking
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
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; this ‘flushed’ water can be collected and used for washing up
choosing plumbing products that have been certified to WaterMark and AS/NZS 4020:2005; and/or have low lead content or are lead free, when renovating or building.
Lead can enter drinking water when service pipes that contain lead corrode, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures. The most common problem is with brass or chrome-plated brass faucets and fixtures with lead solder, from which significant amounts of lead can enter into the water, especially hot water (US EPA).
Corrosive water itself does not pose a health threat when consumed. However, corrosive water, also known as “aggressive water,” is water that will dissolve materials it comes in contact with to create water that is unsafe for consumption.
Corrosion of lead from plumbing systems is of a concern as it is a significant health hazard, will leave no visual sign and has no obvious taste or odour in water. Lead was a very common component of solders used in metal plumbing prior to 1991. A number of factors are involved in the extent to which lead enters the water, including:
the chemistry of the water (acidity and alkalinity) and the types and amounts of minerals in the water,
the amount of lead it comes into contact with,
the temperature of the water
the amount of wear in the pipes,
how long the water stays in pipes, and
the presence of protective scales or coatings inside the plumbing materials.
Lead has been linked to health effects in both children and adults. Lead accumulates in the body until it reaches toxic levels. It can be absorbed through the digestive tract and lungs and is carried by the blood throughout the body. The severity of the effects of lead poisoning varies depending on the concentration of lead in the body.
The impacts of corrosive water on lead pipes in Flint has been well documented – refer to a previous post for the details.
The Australian Drinking Water Guidelines 2018 (ADWG) recognises that water suppliers are not responsible for the actions related to water quality management beyond the point of supply, they should be aware that the drinking water that they supply may interact with internal plumbing and cause unintended water quality issues (either aesthetic or health- related).
The Trade Practices Act 1974 requires water supplied by water suppliers to be fit for purpose, including the conveyance, storage and use of that water within approved plumbing assets, fittings and plumbed-in systems available in water supply areas. In effect, this means that water suppliers have obligations if they are aware of potential negative impacts of mains water on correctly designed and installed plumbing systems.
Some recommended actions that water suppliers can take to minimise the risks associated with interaction of internal plumbing and supplied drinking water are:
Liaise with relevant state-based plumbing authorities to ensure that plumbers use only materials that meet the requirements of AS/NZS 4020:2005: Testing of Products for Use in Contact with Drinking Water.
Liaise with standards-setting bodies and plumbing regulators to ensure that the procedures for approving plumbing materials, fittings and systems are adequate to manage any short-, medium- and long-term risks associated with those materials, fittings and systems when carrying the water supplied in any particular supply area.
Prepare information for customers on water quality issues that may have an adverse impact on their internal plumbing.
Provide advice to customers with large reticulated networks on water quality issues that may arise from having stagnant water within their pipe networks.
Develop and disseminate information to schools, highlighting, in particular, issues related to stagnant water, and suggesting that drinking fountains and other water-using devices be flushed before school returns after holiday periods.
Ensure, wherever practicable, that each property is separately metered so that areas of low flow can be identified.
In liaison with building and site owners and managers and plumbing oversight agencies, consider undertaking investigative monitoring studies to examine the interactions of water as supplied with the plumbing and fittings used in the water supply area.
Recent examples from Australia:
Drinking Fountains in Geelong
In March, the City of Greater Geelong tested a random sample of its public drinking fountains following an alert from Barwon Water regarding the level of lead in water from two fountains in the municipality. These test results found levels of lead and some other metals in some fountains above the Australian Drinking Water Guidelines (ADWG).
In response, the City of Greater Geelong commenced a process of testing its more than 140 public drinking fountains across the municipality.
As a precaution, the City of Greater Geelong is switching off the public drinking fountains found with levels of lead higher than the ADWG.
Perth Children's Hospital
In July 2017, the Western Australian State Government released the Report on Perth Children’s Hospital Potable Water following the discovery of lead levels at above the Australian Drinking Water Guidelines (ADWG) in the drinking water supply of the hospital.
Lead at higher than suitable levels was identified in the drinking water supply in May, 2016. The construction of the new Perth Children’s Hospital had commenced in 2012.
The findings of a review into the issue concluded that:
the source of the lead in the water is from brass fittings that have undergone a process of dezincification;
many of these brass fittings are located within approximately 1200 Thermostatic Mixing Valve (TMV) Assembly Boxes, located within a metre or two of drinking water outlets;
phosphate treatment has been partially but not sufficiently effective in reducing lead levels