The critical importance of water conservation and water loss reduction cannot be overemphasised. It should be made an integral part of the management of freshwater resources and needs to be given prominence in freshwater resource planning. Waste reduction is the first of the several ways of resource conservation, the other means being re-use and recycling.

For water management purposes, the community can be divided into two basic groups: system users such as households, industry and agriculture and system operators such as municipal, provincial and local governments and privately owned suppliers. The users have a choice of a number of different practices, which promote or enhance the efficiency of their use. These practices fall into two basic categories: engineering practices, based on modifications to hardware, e.g., plumbing and fixtures or water supply operational procedures; and behavioural practices, based on changing water use habits. Engineering practices are generally technical or regulatory measures, while behavioural practices typically involve market-oriented measures. These measures collectively affect water use and reduce waste and loss from the source, which is known as “demand management” measures.

Such measures include leak detection; waste reduction; investment in appliances, processes, and technologies that reduce water input without reducing consumer satisfaction or output - treatment of industrial effluents and wastewater to a standard suitable for recycling and reuse; and reallocation of freshwater resources to the area of greatest social good.

Policies that encourage demand management include pricing water at an economical rate, charging for pollution or community-based pollution control practices, regulating and restricting specific water uses, exhorting and informing the consumers of the ways and means of reducing waste and recycling and encouraging water trading among and between users.

Water conservation practices can be followed by residential, industrial, commercial, and agricultural users. They can also be followed by local utilities or regional water supply plants. Low-flow plumbing fixtures and retrofit programmes are permanent, one-time conservation measures that can be implemented with little or no additional cost over the lifetime of the fixtures. In some cases, these fixtures can even save the residents money over the long term. The most commonly recommended low-flow plumbing fixtures are pressure reduction devices, toilet displacement devices, low-flush toilets, low-flow showerheads and plumbing modifications for grey water reuse. Since low-flush toilets use less water, they also reduce the volume of wastewater produced. Even in existing residences, replacing conventional toilets with low-flush toilets is a practical and economical water-saving alternative. Showers account for about 20 per cent of the total indoor water use in any household. Properly designed low-flow showerheads, currently available, are able to provide the quality of water delivery found in higher volume models.

Domestic wastewater composed of wash water from kitchen sinks and tubs, clothes washers, and laundry tubs is called grey water. Homeowners can use grey water for home gardening, lawn maintenance, landscaping, and other uses that do not require potable water. The level of contamination of grey waters is minimal; however, the plumbing modifications needed to make use of this water should not allow its contamination by wastes from toilets, which have the potential to spread disease, cause undesirable odours, and result in aesthetic degradation of homestead yards and gardens.

Water conservation in landscaping can be accomplished by using plants that need little water, thereby saving not only water but also labour and fertiliser. Careful landscape design can significantly reduce water use. In addition to the selection of the plant species to be used in landscaping, practices such as the use of low precipitation rate sprinklers that have better distribution uniformity, bubbler/soaker systems, or drip or point irrigation systems can also conserve water used for landscaping purposes.

Water-saving irrigation practices fall into three categories: field practices, management strategies and system modifications. Examples of these practices include, respectively, the chisel plough aeration of extremely compacted soils, furrow diking to prevent uncontrolled runoff, and levelling of the land surface to distribute water more evenly. Improved irrigation scheduling can reduce the amount of water required to irrigate a crop effectively by reducing evaporative losses, supplying water when most needed by the irrigated plants, and applying the water in a manner best suited to the plants being irrigated. A careful choice of irrigation rate and timing can help farmers maintain yields with less water.

Management strategies involve monitoring soil and water conditions and collecting information on water use and efficiency. The methods include measuring rainfall, determining soil moisture levels, monitoring pumping plant efficiency and scheduling irrigation.

Water recycling is yet another measure that can significantly reduce water loss. It is the re-use of water for the same application for which it was used initially. Recycled water might require treatment before it can be reused. Cooling water recirculation and wash-water recycling are the most widely used water recycling practices. Recycling water within a recirculating cooling system can significantly reduce water consumption by using the same water to perform several cooling operations. The water savings are generally sufficiently substantial to result in an overall cost saving to the industry. Such savings can be even greater if the waste heat is used as a heat source elsewhere in the manufacturing process.

Three cooling water conservation approaches are typically used to reduce water consumption: evaporative cooling, ozonation and heat exchange. Another common use of water by industry is in the use of fresh or deionised water for removing contaminants from products and equipment. The processes required to produce de-ionised water from municipal water can be used to produce de-ionised water from used wash water. It is also possible to blend used wash water with raw water, resulting in an overall water saving.

Public information and education programmes can be undertaken to inform the public about the basics of water use and conservation. Awareness campaigns should be developed for specific applications targetting specific users or age groups; for example, for housekeepers, encouraging domestic water conservation, or for schoolchildren, to provide information on the broader implications of water conservation for future consumption, the environment and other uses. The programmes should provide guidance on how the user groups and individuals can participate in conservation efforts. As water gets scarcer, water experts foresee wars over water in the near future. It is time to take concrete measures worldwide to conserve water and make the most efficient use of this natural resource.

The writer is a civil servant, columnist and public policy analyst