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事實上，提高用水的效率能夠創造一個新的供水來源。國際水資源缺乏問題專家Sandra Postel說，現在已經有了技術和方法，能夠減少工業用水需求40~90%，減少城市用水需求30%或更多，減少農業用水需求10~50%，同時又不會減少經濟產出，也不會降低人們的生活質量。在發展中國家，水需求管理能夠節約資金，又能夠避免生態遭到破壞，還使得無法用到水的人們也能夠有水用，從這個角度來看，水需求管理的潛在利益是非常大的。
在辛巴威召開的聯合國大會1998年淡水管理會議上，辛巴威水資源管理專家S. Mtetwa描述了水需求管理計畫的目標：
「水需求管理的目標在於：
▲保衛將來幾代人用水的權利；
▲限制水需求；
▲確保公平的分配；
▲保護環境；
▲將一單位水的社會經濟產出擴大到最大；
▲提高用水的效率。」
需求管理包括幾個節水的方法，包括經濟政策，引人注意的水價，法律和規範，如限制某種水的使用；公眾和社區的參與，確保解決方法可行並有公眾的支持，在技術上予以解決，如安裝水流限制器。降低水和能源使用的關鍵在於減少消耗的水量。不能只是從技術的角度來考慮需求管理。節水技術方法總是必須考慮經濟、法律、機構和政治等方面。
以下就是減少需求具體方法的列表。大多數都是為地方供水方或政府機構用水而設計的。民眾應當施加壓力，確保水公司和政府盡可能地做到這些事項。
減少全國或地區內的水浪費：
▲對整個系統進行審查，對漏水進行監測，並予以修復。在具有水管系統的種族隔離地區，如Soweto鎮區，就因漏水而失去了50%的供水。在納米比亞的溫得和克，也因不斷漏水的配水系統而失去了33%的水。
▲在社區、公司和學校中進行公共資訊專案。（請見資料來源，查詢適用於南非學校的良好的用水審查方案。）
▲計算所有新的水管連接處，修整既有的連接處。
▲按照維持人類健康所需的「生命線」需水標準（世界健康組織規定是50公升/天），然後再制定適當的水價。「非節約型」的價格不能為減少水的使用量提供動力。這種制價方式的特徵是，當水價降低、用水量就會增加；對消費者每份帳單的固定收費，而不管他用了多少水，或在定價過程中典型的帳單是由高額的固定收費和低廉的商品收費來決定的。節約定價激勵消費者減少平均用量或洩漏的水量，或兩者兼得。節約型的定價方法包括下列任何一項：隨著用水量增加而價格上漲；隨季節而變的水費；超量用水須支付額外款項，以降低乾旱月份的高峰需求；制定的水價係根據長期的邊際成本，或把下一個單位生產能力加入系統的成本。
▲為用水設備和灌溉裝置、及新的工業和商業運作過程建立效率標準。
減少各個家庭的用水浪費：
▲調查用水狀況，檢查有無漏水部位，有無浪費水的器具和灌溉設備。
▲制訂能刺激高效率洗衣機和其他大用水量設備發展的財政策略。
▲制訂配置或直接安裝低流量的淋浴噴頭、抽水馬桶或便池排水設備、水龍頭充氣裝置的策略。
▲要求游泳池和溫泉加蓋，以減少水的蒸發。納米比亞已經研究這個問題，並且發現Windhoek的每個水池每年都會損失約40立方米的水量。要求加上塑膠蓋之後，已經降低這類損失近95%。
▲為現有的水力發電設備和熱力發電設備重新安裝效率更高的發電機和渦輪機（水輪機或汽輪機）。
▲安裝屋頂雨水收集裝置。
▲推廣智慧型用水的園藝技術。
減少大型綠化區域（公園、運動場、大型旅館）浪費用水
▲提供節水專案、員工培訓和經濟刺激專案。可包括綠化地區用水調查、自願制訂用水預算、安裝專用的園藝量水儀錶、開展灌溉系統維護和灌溉系統設計方面的培訓；提供經濟刺激以提高灌溉系統的效率（提供貸款、折扣和補助金給用水效率高的灌溉系統。）
▲禁止用水浪費，比如禁止在所有新建的商業洗衣設備中使用非循環式裝置。
▲對於新的景觀專案，為客戶提供配合當地氣候的景觀設計、有效的灌溉設備和管理方面的資訊。
▲在用水管理機構處安裝與氣候相適應的用水效率高的園藝裝置。
【流失的水】一個即使只有輕微漏水的抽水馬桶，每年也會浪費多達75,700公升的水。一個每分鐘漏50滴水的水龍頭，一年總共可浪費掉1,838公升的水。更有甚者，一座沒有加蓋的游泳池，每週會因蒸發而損失多達1,000公升的水。
版權歸屬 國際河網IRN，環境資訊協會（陶俊 譯，吳國玢，李瑞玉 審校）
中英對照全文：http://e-info.org.tw/issue/water/2001/issue-water-irn01081301.htm
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Using water more efficiently can, in effect, create a new source of supply. According to Sandra Postel, an expert in international water scarcity problems, technologies and methods are now available which could cut water demand between 40 and 90 percent in industry, 30 percent or more in cities, and between 10 and 50 percent in agriculture without reducing economic output or quality of life. In developing countries, the potential benefits of water demand-side management programs are huge in terms of money saved and ecological damage avoided, as well as freeing up water supply to extend coverage to the
unserved.
Water management expert S. Mtetwa of Zimbabwe described the goals of demand management programs for water at a 1998 United Nations conference on freshwater management in Zimbabwe:
"Water demand management aims to:
▲safeguard the rights of access to water for future generations;
▲limit water demands;
▲ensure equitable distribution;
▲protect the environment;
▲maximize the soci-economic output of a unit volume of water, and
▲increase the efficiency of water use."
Demand management includes several approaches to conserve water, including economic policies, notably water pricing; laws and regulations, such as restrictions on certain types of water use; public and community participation, to ensure that solutions are workable and have public support, and technical solutions, such as installing water flow restrictors. Reducing the amount of water consumed is key to cutting both water and energy expenses. Demand management cannot be thought of only from a technical angle. Water-saving technical measures always have economic, legal, institutional and political aspects that must be considered as well.
Below is a checklist of specific ways to cut demand. Most are designed for use by local or regional water suppliers or government agencies. Citizens should press to ensure their water utilities and governments are doing as many of these things as possible.
To reduce water wastage nationally or regionally:
▲Do overall system water audits, leak detection and repair. In places with apartheid-era water pipe systems, such as the township of Soweto, up to 50 percent of water supplies are lost due to leakages. In Windhoek, Namibia, up to 33 percent of water is lost by leaking distribution systems.
▲Offer public information programs in communities, businesses and schools. (See Resources for a good South African water audit program for schools)
▲Meter all new connections and retrofit existing connections.
▲Price water appropriately, after providing at low- or no- cost a "lifeline" level of water as required for human health (considered to be 50 litres/day by WHO). "Non-conserving" pricing provides no incentives to reduce use. Such pricing is characterized by rates in which the unit price decreases as the quantity used increases (declining block rates); rates that involve charging customers a fixed amount per billing cycle regardless of how much water is used, or pricing in which the typical bill is determined by high fixed charges and low commodity charges. Conservation pricing provides incentives to customers to reduce average or peak use, or both. Conservation pricing can include any of the following: price increases as the quantity used increases; seasonal rates; excess-use surcharges to reduce peak demands during dry months; rates based upon the long-run marginal cost or the cost of adding the next unit of capacity to the system.
▲Develop efficiency standards for water-using appliances and irrigation devices, and for new industrial and commercial processes.
To reduce water wastage in individual households:
▲Conduct water survey to check for leaks, water-wasting appliances and irrigation practices.
▲Develop strategies to offer financial incentives for high-efficiency washing machines and other high water-use appliances.
▲Develop strategies to distribute or directly install low-flow showerheads, toilets or toilet displacement devices, and faucet aerators.
▲Require swimming pool and spa covers to reduce evaporation. Namibia has studied this problem and found that each pool in Windhoek loses about 40 cubic metres of water per year. Plastic covers are now required, and have reduced this loss by up to 95 percent.
▲Refit existing hydroelectric and thermal power generating equipment with more efficient power generators and turbines.
▲Install rainwater roof-collectors.
▲Promote water-wise gardening techniques.
To reduce water wastage for large landscape water users (parks, sports fields, large hotels)
▲Offer conservation programmes, staff training and incentive programmes. May include landscape water use surveys, voluntary water use budgets, installation of dedicated landscape meters, training in irrigation system maintenance and irrigation system design; financial incentives to improve irrigation system efficiency (loans, rebates, and grants for water efficient irrigation systems).
▲Prohibit water waste, such as non-recirculating systems in all new commercial laundry systems.
▲For new landscaping, provide information on climate-appropriate landscape design, efficient irrigation equipment and management to customers.
▲Install climate-appropriate water efficient landscaping at water agency facilities.
A toilet with even a tiny leak can waste 75,700 litres of water a year.
A tap leaking 50 drops a minute adds up to 1,838 litres a year. And uncovered swimming pools lose up to 1,000 litres per week to evaporation.
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