In Australia, the brand TransTank International manufactures portable water tanks from specially formulated polyethylene for transport and static applications. In some cities, installation of rainwater tanks may be mandatory, or may help a new building be approved. For example, in Victoria, Australia new houses which have rainwater tank connected to all flush toilets are given an additional 1-star of the required 5-star House Energy Rating. Some governments subsidise purchases of rainwater tanks or provide rebates in areas where they are considered an important means of water supply augmentation. In the United States, Santa Fe County, New Mexico requires a rainwater collection system on all new construction with greater than 2,500 square feet, mostly for landscaping purposes and to prevent over-reliance on wells but in some instances because ground water is prohibitively expensive to obtain, if even available.