The second part consisted of a variable charge based on a charge per kilolitre of water consumed. After imposition of the user-pays tariff, average consumption declined 10 percent in the first year and another ten percent in the next year. Nine years after its introduction, consumption was reduced by 30 percent against the pre-charge trend. It is not always necessary to raise new or additional taxes to provide incentives for cleaner production. The provision of tax deductions or accelerated depreciation provides an incentive to change behaviour in a similar way that taxes do it changes the relative economic price of taking a particular action.
Many countries provide some form of tax relief for environmental technology.
The most common form is accelerated depreciation on certain plant or equipment, but many countries also provide investment tax credits for certain types of investment, such as pollution control equipment or research and development. The Australian Tax Office currently allows a range of deductions for environmental expenditure. Currently, it appears that these tax concessions do not provide a specific incentive for investing in cleaner production as they allow depreciation allowances for environmental plant and equipment only at the same rate as for investments in 'normal' plant and equipment. However, it must be noted that these existing concessions have not been widely promoted and so their effectiveness has not been fully tested. To increase the incentive for enterprises to adopt cleaner production, some European countries have introduced accelerated depreciation allowances for environmentally clean technologies.