The purpose, scope and definition of a water audit is presented in clear and concise language suitable for UK businesses. Water audits simplify the process of assessing water use and provide a clear understanding of the savings that can be made. A water audit is an assessment of how water is used within a site or organisation*, what volume of water use is required for the operation of the business, and what corrective actions can be made to minimise water use. Water audits identify sources of water use within a business. With a defined business, a water audit should include data collection for a defined period, along with examination of utility bills, a site walkover and key interviews.
Water is essential for nearly every operation, but its consumption is frequently taken for granted. Producing products and providing services can use thousands or even millions of litres of water per business. Water utilities provide water metering and charging services; however, very few enterprises conduct a water audit, as it is often assumed that the metered consumption is accurate. However, there are clear regulatory, commercial, environmental, and social pressures on businesses in the UK to conduct routine water audits.
2. What is a water audit
What is a water audit?
A water audit provides a simplified overview of water use in a building or business, clearly identifying areas for water savings and reductions in water bills, while meeting regulatory obligations. Undertaking a detailed water audit is an integral part of any sustainability agenda. If a business is not conducting a water audit, then it is likely missing opportunities to manage consumption, save costs, and reduce operational risk. It is much easier and less time-consuming than one that focuses on carbon, energy, or waste.
A water audit is a detailed assessment of water use in a building or business. The aim is to quantify and review how much water is used, who uses it, how it is being used (or misused), and what can be done to reduce consumption. Although most companies have metered water supplies, few truly understand how that water is being utilised within the business, and the accuracy of the data is often uncertain. A water audit provides insights into the amount of water being used, its comparison with previous years, the source of water from different parts of the business, and whether it is being used efficiently. The information can support operational decisions, demonstrate effective water management, and identify potential cost savings. It can also help satisfy the increasing number of regulations and guidelines aimed at reducing water use in businesses, such as the European Union Water Framework Directive and the UK Government Code of Practice for Water.
The key data needed for a water audit includes: water bills for at least the past three years; water consumption data broken down by meter, if available; available details of water-using equipment, systems, and processes; and, where possible, information on what other similar businesses are doing. Key metrics to be calculated include: total water consumption, the cost of water per unit (i.e., per m³ or per litre) and per staff member, and, if possible, benchmarking data to indicate whether consumption is in line with industry averages and good practice. At the end of the audit, a one-page summary of the findings and conclusions is produced, along with the detailed supporting data.
3. Why UK businesses should audit water use
UK businesses should check their water use for several reasons. Although one of the most affordable utility costs, water is a precious resource in high demand. Approximately 70% of the world’s supply is allocated to agriculture, and droughts are on the rise due to climate change. Water suppliers are required, under the Environment Act 2021, to develop Water Resources Management Plans that ensure reliable supplies for customers until at least 2050. Auditing water use helps organisations to work towards these common goals.
A water audit helps businesses to identify savings, both financial and resource-based. It highlights past inefficiencies and current areas for concern; some are relatively low-cost to rectify, while others may require more substantial investment. Water metering is often incomplete. Fitting additional or improved metering can provide valuable data for a site and is inexpensive to achieve, but is sometimes overlooked. The results of an audit can also help to underpin a company’s environmental, social, and governance (ESG) reporting.
4. How a water audit works
Although audit quality varies, an audit typically consists of six stages. Initial scoping determines expectations, informs bid proposals, and establishes responsibilities. The auditor typically requests background information within a week and meets with personnel who have relevant knowledge.
The auditor reviews existing metering data or collects water consumption data if not available to identify usage patterns and potential inefficiencies. Demand-side processes are examined and operational hours checked to clarify the interaction between processes and metering. During a site walkthrough, metered processes receive attention, along with those likely using more water than expected. Unmetered water usage is discussed with knowledgeable personnel, especially for irrigation purposes. All potential areas of excessive or poorly managed water consumption are profiled.
Costs for water supply, effluent disposal, and cleaning are collated, listing major processes where possible. Costs follow a simplified format grouping demand subcategories, not every supply contract. Missing data might delay the audit, but missing reports are usually manageable. The auditor details information and sources required and indicates a timeline for completion.
Using the compiled data, the auditor analyses water consumption, identifying key metrics such as cubic metres consumed per unit produced, cubic metres per capita, cubic metres per area for irrigation, and toilet flushing per occupancy. Comparisons with indicators and benchmarks from other operations, similar processes, and previous audits indicate efficiency. Findings describe areas of concern identified during the data review, including inefficiencies, leaks, poorly installed or located metering, and irrigation systems without effective metering. Simple corrective actions, such as increasing staff awareness or improving the response to reported leaks, are suggested.
5. Benefits of a water audit
Saving water is always good news for everyone involved. A water audit examines water use in detail, identifying areas where savings can be made and converting those opportunities into actionable recommendations. A successful audit can save water and money, help meet corporate sustainability targets, demonstrate compliance with regulations, reduce business risks, and improve both the bottom line and the business’s reputation.
The simplest summary is that a water audit will result in an overall reduction in water consumption, which is beneficial from both financial and environmental sustainability perspectives. Figure 3 shows how this looks. It can also be measured as a reduction in water charges, and for those customers with meters, it is also a reduction in trade effluent charges. In some cases, reducing the volume of water being abstracted under an abstraction licence may help with securing renewals. Measurement reduces some of the uncertainties associated with a water audit, making it easier to demonstrate and quantify the audit's value.
6. Steps to prepare for an audit
Before embarking on a water audit, gather relevant information to simplify the process and obtain the best outcome. Consider the following actions.
Identify data to gather. Assemble current water bills from internal records or service providers, including frequency and costs; assess monthly and annual consumption; compare historical usage; and check industry benchmarks. This information provides the auditor with a basis for discussion and a reference point for any site visits.
Engage relevant stakeholders. Identify anyone who can offer insight on water use, including facility and environmental managers; sales, production, and finance staff; hotel duty managers and head housekeepers; and health and safety and sustainability sponsors. Consider circulating a questionnaire to gather comprehensive, up-to-date, and accurate details, ensuring key individuals understand the purpose of the audit, the benefits for their area, and the confidential nature of responses.
Could you determine which sites or operations to review? If the audit covers a single site, it should focus on the primary kitchen, bathroom, and laundry facility or area of highest water use. If the audit encompasses a wider range of facilities, begin with the site that consumes the most water, followed by additional locations in order of decreasing consumption. Review the audit limits and the appropriate level of detail to suit the client's objectives and budget.
Specify a timeline. Prepare a simple schedule detailing the data to be gathered, the source of the data, the expected collection times, the schedule for auditor site visits, and the expected completion date for the final report. Maintain regular contact with the auditor throughout the process to ensure that all information is delivered promptly, allowing adequate time for analysis and resulting in a timely report.
7. Common findings and fixes
Common Water Audit Findings and Their Remedies
Water audits find inefficiencies and savings opportunities by scrutinising water use data and business practices. Among the common discoveries are leaks and burst pipes, poorly maintained plumbing, oversized toilets, unattended pressure-irrigating systems, and over-frequent watering, particularly of ornamental plantings. Often, meters for whole properties are missing or underused.
Detecting leaks can seem daunting, yet it’s largely a simple if sometimes tedious oversight. Regular meter checks to check for unwanted flows, especially late at night or early in the morning when no one is using water, are vital. Large consumption spikes when demand should be negligible indicate leaks. Even the best monitoring is still prone to missed leaks, but many (e.g., constant drops, wet patches) are easy to catch with simple visual checks. Regular checks and prompt repairs will also reduce water-borne diseases, such as legionella.
8. Choosing an audit provider
Organisations offering water audits are not required to be accredited or certified, unlike for example energy auditors, but many will still advertise certain qualifications and endorsements. These can include ISO standards such as ISO 14046, the International Standard for Water Footprint Assessment, and ISO 50001, which sets out how to identify and implement improvements in energy management systems. Registration with the Environment Agency's Carbon Reduction Commitment (CRC), although now closed to new entrants, provides a level of credibility because CRC-registered organisations have had to complete a water management plan or conduct a water audit and make such data publicly available. The Water Stewardship Standard (AWS Standard) is borne out of the water audit accreditation body, the Alliance for Water Stewardship (AWS). Adopted as the baseline methodology for grater water stewardship assessment, the standard is supported by various government departments including Defra.
An audit can also be performed by accredited ISO 1401 or ISO 50001 registrars. Their services may be offered at a discounted rate of less than £1,000 since clients are at a lower risk due to the limited scope of the audit. At the other extreme, a number of companies advertise their services specifically for audits. Nevertheless, it is sensible for larger clients seeking a comprehensive on-site audit to view these stakeholders in the context of the overall audit programme. Several of the more enjoyable services also list as an additional service flow measurements and monitoring for water efficiency calculations. Two organisations have conducted audits at over 1,000 premises throughout the UK and shown in many instances that a simple walkthrough identification of potential water conservation measures can yield savings of up to 75% of water used – a far greater than expected return, often making buildings without prior conservation measures the best candidates for an audit.
9. Cost and funding considerations
The cost of a water audit depends on the expertise of the provider and the complexity and volume of data to review. For a small business—perhaps with a single site, low water use, and little or no metered drainage—an audit may cost around £1,000, while for a larger business, with several sites, associated support functions, high drainage volumes, and more sophisticated processes, the cost could be £5,000 or more. Water audits may therefore qualify for grant funding through schemes such as the Resource Efficiency Grant Scheme in England.
A water audit should identify low-cost or no-cost opportunities to conserve water and reduce costs. By quantifying the financial benefits and detailing the required investment, the audit provides a compelling business case for addressing these improvements. Although some opportunities may be amenable to internal action, others may require external investment; however, the payback periods will usually make these attractive.
10. Conclusion
A water audit is a straightforward way to simplify water use and identify savings. This simplified explanation defines a water audit, outlines what it covers, why it matters, and who it is for. It aims to help UK businesses prepare for an audit, clarifying how audits work and what benefits they deliver. Auditors should consider common savings areas and methods for selecting a suitable provider.
For UK businesses, a water audit is a straightforward way to simplify water use and identify savings. What is a water audit? Why does it matter? And what does it involve? A water audit clears away the jargon and provides the answers. A water audit examines how water is used, identifies ways to reduce consumption, and discovers opportunities to cut costs and mitigate other water-related risks. It is a structured review of water-using activities at a site, often focused on the demands of industrial operations. The audit addresses growing regulatory concerns about UK water security, offers an opportunity to save money, and reduces the environmental impact of operations.
UK businesses should consider conducting a water audit now for two key reasons. First, it will help them comply with an increasingly complex range of environmental regulations. Additionally, it is a straightforward win on the road to enhancing sustainability. Compared to energy savings, water savings are often less well understood and poorly executed. As a result, the numbers can add up quickly and yield a fast payback. Conducting a water audit helps identify waste, missed opportunities, and simple solutions. Water meters may not be correctly positioned and therefore not provide useful operational data. A lack of metering may mean nobody knows how much is being discharged to sewers, a critical number for any business engaged in food or drink production, bathing, washing, or laundry. And then there are leaks.
