Water audit is a systematic process of objectively obtaining a water balance by measuring water flow from the site of water withdrawal or treatment, through the distribution system, and into areas where it is used and discharged. Conducting a water audit involves calculating water balance and use and identifying ways to save water. (Annual water audits by the industries)

Water audit involves a preliminary water survey and a detailed water audit. An inadequate water survey is conducted to collect background information regarding plant activities, water consumption and discharge pattern, water billing, rates, and water cess. After the analysis of the secondary data collected from the industry, a detailed water audit is conducted, which involves the following steps:

• On-site training and discussion with the facility manager and personnel
• Water system analysis
• Quantification of baseline water map
• Monitoring and measurements using pressure and flow meters and various other devices
• Quantification of inefficiencies and leaks
• Quantification of water quality loads and discharges
• Quantification of variability in flows and quality parameters
• Strategies for water treatment and reuse or direct use

A detailed water balance is finally developed. Water quality requirement in various user areas is mapped, which helps develop ‘recycle’ and ‘reuse’ opportunities. The detailed water audit report contains the following:

• Water consumption and wastewater generation pattern
• Specific water use and conservation
• Complete water balance of the facility
• Water saving opportunities
• Method of implementing the proposals
• Full description and figures
• Investment required

Industries can undertake the following measures for water conservation:

• Setting up norms for water budgeting
• Modernization of industrial processes to reduce water consumption
• Recycling water with a re-circulating cooling system
• Ozonation cooling water approach can result in a five-fold reduction in blow down when compared to traditional chemical treatment
• Reduction in the reuse of de-ionized water by eliminating some plenum flushes, converting from a continuous flow to an intermittent flow system, and improving control of the use
• Use of wastewater for gardening
• Proper processing of effluents to adhere to the norms of disposal.