The ACT Government has demanded the Independent Competition and Regulatory Commission assess the potential human rights implications of a proposal to hike Canberrans' water supply fees by $500 over the next decade.
A government submission into the commission's water tariff review has hit out at the proposal outlined in a draft report released in September this year.
The commission proposed two options for changing the current two-tier water tariff system, both of which would replace it with a higher annual supply charge and a single lower per kilolitre charge.
Under the proposed changes, the annual water supply bill charged to all users could rise from $101 to at least $600, a move to help recover the costs of delivering water to all Canberrans.
But the government has hit out at the tariff structure changes proposed, as well as a second proposal to allow Icon Water to set water prices, within a commission-determined framework.
Deputy Chief Minister Yvette Berry said that under the proposals put forward, "a significant proportion of Canberra's vulnerable and low income households would be unfairly punished".
"This would be a devastating outcome for households who would feel the impact of increased water charges the most," she said.
Both the ACT Human Rights Commission and the ACT Council of Social Services has criticised the proposal and its potential impact on Canberra's lowest-income residents, with the ACTCOSS previously warning an increase in the charge could see rents rise as a result.
The government's submission also called on the commission to include detail in its final report "that demonstrates an assessment of the consistency of the proposed tariff reforms with the requirements of the Human Rights Act".
While the government noted the proposal was designed to "improve the economic efficiency of the water tariff structure", it has urged the commission to ensure it was meeting its legislative objectives to balance those concerns with the potential "adverse" social and environmental impacts.
"In particular, the notes that even with the transitional approach outlined, the proposed tariff reforms would result in substantial continuous real increases in water bills for most ACT households over (the decade)," the submission reads.
The submission also found that under the commission's proposed changes, the "75% of ACT households that use less than 300 kilolitres per annum would face higher water bills following the transition".
Government analysis of the impacts of the proposed changes showed under both options, the average residential unit owner in Canberra would face water bill price rises of between 64 per cent and 87 per cent over 10 years, while standalone home owners would see a 34 to 38 per cent rise in the same period.
But the largest "commercial users" in the ACT, who use at least 1,000 kilolitres a year, would instead benefit from a 38 to 51 per cent fall in their average water bills.
The submission also argues the changes could see bigger users using more water, potentially affecting the ACT's obligations under the Murray-Darling Basin Plan.
"Given the significant population growth expected over the next several decades in the Territory, if consumption levels were to return to levels such as those recorded in the early 2000s, there would be a long-term impact on the government's capacity to fulfil its obligations under the Murray-Darling Basin Plan," the submission reads.
The commission plans to hold a public forum on the water and sewerage tariff review at 5pm on Tuesday December 6 at the Waldorf on London hotel, 2 Akuna Street, which was originally proposed to be held in October, but was delayed due to the election.