Reducing Exposure to Metals in Drinking Water
Lead contamination in drinking water remains a critical public health issue in Australia and has been highlighted by studies and reports, including the “Lead in Plumbing Products and Materials” review ¹ and findings from “Lead Leaching from In-Line Fittings: Perth Children’s Hospital Perth.” ² Both reports document the risks of lead leaching from plumbing materials and these are addressed by new legislation with significant attention on brass components and lead free service lines.
Managing Lead Contamination in Building Plumbing Systems
In the case of Perth Children’s Hospital, elevated lead levels were traced back to in-line fittings within the water supply. This underscores the importance of understanding the materials used in plumbing systems and the conditions that exacerbate lead leaching. These findings provide important lessons for building designers and hydraulic engineers tasked with managing water quality in existing structures.
Factors Influencing Lead in Buildings
The primary factors that contribute to lead contamination in buildings’ drinking water systems include:
• Plumbing Materials: Brass fittings and components that contain lead which can leach into water.
• Water Chemistry: Acidic water (low pH), high chlorine levels and the use of disinfectants like chloramine can increase the corrosivity of water, thereby accelerating the release of lead from plumbing materials.
• Stagnation: Water that remains stagnant in pipes for extended periods (e.g. In underutilised buildings or dead-end pipes) allows more time for lead to lead into the water supply increasing the lead concentrations.
What can be done?
To manage lead contamination in water systems, building operations should implement a series of measures that target the factors influencing lead release.
These recommendations are designed to minimise the risk of lead contamination and ensure water safety for building occupants.
1. Choose Low-Lead or Lead-Free Materials
• Plumbing Components
For any plumbing works in building plumbing systems, use only certified low-lead or lead-free fittings and fixtures. Brass components should be chosen carefully, ensuring they meet lead-free standards (0.25% lead or less).
• Corrosion-Resistant Materials
Preference for materials which do not contribute to lead contamination.
2. Optimise Water Chemistry
• pH Control
Maintain water at a neutral or slightly alkaline pH (7.5–8.5), which minimises corrosivity and reduces the dissolution of lead from pipes.
• Use of Corrosion Inhibitors
Incorporate corrosion inhibitors, such as orthophosphates, into the water system to create a protective layer inside pipes and prevent lead leaching.
3. Implement Stagnation Management Practices:
• Flushing Protocols
Establish regular flushing protocols in buildings where water usage is intermittent. Automatic flushing systems can ensure that water does not sit stagnant in pipes for extended periods.
• Dead End Pipe Management
In buildings with complex piping systems, avoid or minimise length of dead-end pipes or ensure they are flushed regularly to reduce stagnation.
Advisory Note: Reducing Exposure to Metals in Drinking Water
4. Monitor Water Quality Regularly
• Boundary Quality Checks
Although Australian Standard AS 3500.1 Plumbing and Drainage, Part 1: Water Services. does not mandate water quality testing at the property boundary, designers should include routine water testing at this point to identify the water composition entering the building from the mains supply. Water quality testing can provide early warning of potential lead issues and inform decisions about further internal system testing.
5. Sampling and Testing
• Adopt Sampling Protocols
Implementation of regular water sampling methods can be applied to monitor for lead. These include:
• Random Day Time (RDT) Sampling - a random daytime sample is a water sample taken at a random time during the workday from a tap without flushing it first.
• 30 Minute Stagnation Sampling - a water sampling method that involves letting water sit in pipes for 30 minutes after a full flush.
6. Public Health and Education
• Educate Building Managers
Provide clear guidelines for building managers on the risks of lead contamination and the importance of regular system maintenance. Pubilc spaces like schools and hospitals should be prioritised for lead-free upgrades.
• Consumer Awareness inform building occupants about simple steps they can take, such as flushing taps after periods of inactivity, to reduce exposure to lead.
Summary
The 2022 edition of the National Construction Code (NCC) has set new limits on the permissible levels of lead in plumbing products. During this transition period, lead contamination in drinking water poses a significant health risk, necessitating proactive management of exsisting potable water supply systems.
These risks can be mitigated by implementing comprehensive strategies to optimise water chemistry, ensure regular water quality monitoring and by prioritising and choosing safe materials. As such, building operators can significantly reduce lead exposure in buildings, safeguarding public health for years to come.
References
1. Taylor, M. P., Harvey, P. J., Morrison, A. L. (2018). Lead in Plumbing Products and Materials. Macquarie University.
2. McCafferty, P. (2017). Lead Leaching from In-Line Fittings: Perth Children’s Hospital. ChemCentre, Western Australia.
Have you tested your water quality recently?
For further guidance on water quality, please contact:
Chris Frangos
Senior Consultant (Hydraulics) A.G. Coombs Advisory
+61 7 3648 0500 cfrangos@agcoombs.com.au