It's feared hundreds of south-east Queenslanders have been exposed to lead contamination after a Sunshine Coast tradie used lead solder on water pipes.
Anyone who used Brett George Hogan or his company Hot Water One to fix their hot water systems over the past five years are being asked to contact authorities.
Queensland's Building and Construction Comission says almost 800 homes may be affected from Hervey Bay to the north to Logan in the south.
Health Minister Cameron Dick said affected property owners could lower their risk of lead poisoning through some simple steps.
"We're asking residents not to drink hot water from those systems until they are properly checked, do not use hot water out of the tap for cooking if you are one of those homes, and try to minimise your ingestion of water in the shower or bath," he said.
"We think the risk is low, but we will now do a survey on a number of homes, we will now examine the water, see what the situation is and work to rectify that and support those individuals are required."
People requiring health information on lead should contact their GP or call 13HEALTH.
If a home or property owner believes there could be an issue with work done by Mr Hogan, they can phone the QBCC on 139 333 to arrange for a free inspection by the QBCC or a Local Government Authority.