The State Government has no immediate plans to reduce water charges and public transport fares after the repeal of the carbon tax.
Treasurer Mike Nahan said yesterday that he had written to Synergy and Horizon Power to ensure that electricity savings were passed on to households as soon as practicable.
Reduced power bills would be backdated to July 1. But on other fees and charges, Dr Nahan said Treasury would work with the Water Corporation, the Public Transport Authority and other government agencies to identify the effect of the tax repeal.
In 2012, the Barnett government described the carbon tax as an unnecessary and ineffective burden on WA households that would increase power prices 9 per cent, gas 4.2 per cent, water 0.8 per cent and public transport fares 1.5 per cent.
Yesterday, Dr Nahan said the repeal of the tax was a win for all West Australians.
Electricity bills for an average family would fall about 8 per cent (or $126 a year in the city and $267 in regional areas).
Household gas prices were expected to drop 4 per cent.
"Directly, the carbon tax was estimated to cost WA government agencies around $60 million in 2014-15 due to higher prices for goods and services," Dr Nahan said.
Synergy issues about 25,000 invoices each day and expects it will take six to eight weeks for the benefit of the tax repeal to flow to customers.
Because of the timing of the repeal legislation being passed in the Senate, some Synergy customers could get a bill that includes a carbon charge.
In that case, a credit will apply to a future bill.