Some of WA's most disadvantaged households are being slugged credit card-like interest rates on overdue water bills, sparking accusations from the Opposition that the State Government is heartless.
In the wake of water prices rises of 46 per cent since the Barnett Government came to power, it has emerged a significant number of people are being charged 13.5 per cent interest on unpaid invoices.
The revelation comes amid an explosion in the number of customers who have either been forced on to payment plans for their water bills or pursued by the Water Corporation over outstanding debts.
Fresh figures show there were more than 84,000 households on payment plans in 2010-11, compared with 72,600 the previous year.
The number of Water Corporation customers who have been taken to court by the State-owned utility is more than 2500 - an increase of 35 per cent.
The State Opposition seized on the figures to claim the Government was out of touch and entrenching an underclass of people who were increasingly unable to afford their bills.
Shadow water minister Fran Logan said Labor would highlight the issue in the lead-up to next year's election.
"This is usury," Mr Logan told State Parliament. "It is outrageous.
"The Water Corporation is . . . applying (the interest rates) to the poorest people in our society, people who are struggling.
"These are the people the mining boom has forgotten."
Ahead of a forecast 8.5 per cent rise in water prices from July 1, when average bills will jump to $1361, Mr Logan demanded Water Minister Bill Marmion ban the Water Corporation from charging interest rates. He noted State-controlled electricity retailer Synergy did not charge interest.
Mr Marmion said WA water charges were among the lowest in the country but the Government was doing all that it could to help families suffering from price rises. He said customers could apply for funding help through the Water Corporation and the Hardship Utilities Grant Scheme and there were discounts available, particularly for pensioners.
The Water Corporation said customers having trouble paying were offered arrangements at a lower interest rate. Those in "genuine" financial hardship were not charged interest.