that reclaimed water is safe and treated properly for the intended end use. Some water demanding activities do not require high grade water. In this case, wastewater can be reused with little or no treatment. One example of this scenario is in the domestic environment where toilets can be flushed using greywater from baths and showers with little or no treatment. In the case of municipal wastewater, the wastewater must pass through numerous sewage treatment process steps before it can be used. Steps might include screening, primary settling, biological treatment, tertiary treatment (for example reverse osmosis), and disinfection. Wastewater is generally treated to only secondary level treatment when used for irrigation. A pump station distributes reclaimed water to users around the city. This may include golf courses, agricultural uses, cooling towers, or in land fills. Alternative options Rather than treating municipal wastewater for reuse purposes, other options can achieve similar effects of freshwater savings: Greywater reuse systems – at a household level, treated or untreated greywater may be used for flush toilets or to water the garden. Rainwater harvesting and stormwater recovery – Urban design systems which incorporate rainwater harvesting and reduce runoff are known as water-sensitive urban design (WSUD) in Australia, low-impact development (LID) in the United States and sustainable urban drainage systems (SUDS) in the United Kingdom. Seawater desalination – an energy-intensive process where salt and other minerals are removed from seawater to produce potable water for drinking and irrigation, typically through membrane filtration (reverse osmosis), and steam-distillation. Costs The cost of reclaimed water exceeds that of potable water in many regions of the world, where a fresh water supply is plentiful. However, reclaimed water is usually sold to citizens at a cheaper rate to encourage its use. As fresh water supplies become limited from distribution costs, increased population demands, or climate change reducing sources, the cost ratios will evolve also. The evaluation of reclaimed water needs to consider the entire water supply system, as it may bring important value of flexibility into the overall system Reclaimed water systems usually require a dual piping network, often with additional storage tanks, which adds to the costs of the system. Barriers to implementation Barriers to water reclamation may include: Full-scale implementation and operation of water reuse schemes still face regulatory, economic, social and institutional challenges. Low economic viability of water reuse schemes. This may partly be due to costs of