A water balance is a management tool that can be used to show where water enters and leaves your business, and how it's used in between. It provides a way of gathering and presenting information about water use that can help you to:

• understand and manage your water and wastewater more efficiently
• work out where you can cut water and water treatment costs
• detect leaks

Developing a water balance is a straightforward step-by-step process that involves:

• gaining the full commitment of senior management - see making the case for environmental improvements
• conducting a preliminary review - see initial analysis of your water use and disposal
• drawing a diagram of your site, showing the main water inflows and outflows - see make a diagram of your business' water use
• adding the detail and making a water-use spreadsheet - see how to finalise the detail of your water balance and quantify and record your water use
• using the water balance to save money on water use and disposal - see the page in this guide on how to use your water monitoring information to save money

You should make sure you review and update the water balance regularly.

The first step to creating your water balance is to form a broad-brush picture of your water use and disposal. You should find that there is plenty of information available, as well as observations by people who work in your business. You can:

• gather information about your water use from sources such as water meters, bills from Northern Ireland Water, data from flow-meters (if you use them) and machine data
• tell your colleagues, departmental managers and employees what you are doing, and find out their views on current practices
• try to fill in any gaps in your analysis - an overnight or weekend test using your water meters might show that you have a hidden water leak

The amount of detail you need will depend to some extent on your business - for example if you manufacture products that use a lot of water, you'll need more detail. However, even if your business uses relatively little water you will benefit from a detailed analysis of use and disposal.

Once you have gathered all of the initial information together for your water balance, you can make a plan of your worksite, showing where water is used and disposed of. You should include the position of water meters and flow meters, and remember to include locations where there is a high level of evaporation, such as heating systems or laundry rooms.

If you manufacture products that include water, include those in your diagram. You are looking at the major activities that use water in your business, so you need to identify where:

• water comes in
• there is a function and a use of water
• water or waste leaves the site

Your drawing will give you the overall picture, and may enable you to identify quick wins where you can make immediate savings for relatively little cost.

In a block diagram, each major activity is represented by a box with a list of the major water uses and an arrow showing the source of the water and how it is disposed of. You can put water inputs in a list at the top of the diagram with outputs at the bottom.

Use the same units throughout - for example cubic metres per day or week - and try to make as complete a picture as you can, using the information you have gathered from the initial review. You might not be able to account for all of your water use, but you may be able to fill in gaps by adding detail to your water balance by carrying out more measurement and investigation - see how to finalise the detail of your water balance.

Your initial water balance may have identified less than 80 per cent of your water use. Depending on how much water you use, it could be cost-effective to increase this to 95 per cent. You can do this by:

• working out which activities and processes use the most water
• measuring flows to obtain more detail
• continuing to review and measure until it is no longer cost-effective to do so

Identify water supplies

Find out where your water comes from and how it is treated and distributed on-site including:

• how it's supplied, eg mains, river water, reservoir or borehole
• how it's stored, eg in tanks or lagoons, and the capacity
• whether water is treated on-site and how
• how water is transferred, eg by pump, gravity or manually

Investigate water use

Use one or more of the following to look into water use:

• walking around the site to find where water is used
• looking at location and numbers of water meters
• talking to staff about where water is used
• tracing water-supply pipes from sources to use point, if possible
• finding drawings of the water supply system

You also need to gather information such as:

• number of employees on-site or per shift
• type of product being produced
• number of lines operating
• processes such as rinses and washing cycles

Making a plan as you go along can help you to keep track of where you are, particularly if there is no diagram of the water supply and distribution system.

Identify effluent sources

To identify sources and effluent (liquid waste) disposal methods, you should:

• look at plans of your effluent drainage, surface water drainage and foul sewer systems - if these don't exist, make your own diagrams
• mark the location of any effluent meters or sampling points
• walk around the site looking for sources of effluent and wastewater
• talk to staff to get their input
• include any liquid wastes and slurries taken off site by tankers

Other water losses

Look at other ways in which water leaves your site:

• in your products - eg in drinks manufacture
• in steam, during product manufacturing or processing - such as laundries or some food processing

You will need this information to complete your water balance.

Having created the water balance, you need to quantify and measure each element. Put all major water uses and effluent (liquid waste) sources in order and, starting with the largest, work out quantity and frequency of use.

There are various ways of measuring water use:

• water meters
• flow meters
• calculations from manufacturers' brochures or handbooks
• estimates based on your knowledge of the process
• timing how long it takes to fill a container of a known volume

To measure effluent, you can use similar methods, although in some cases - for example washrooms or rinse processes - effluent flow may often be the same as water use. If waste is collected by an outside contractor, they should be able to provide data.

You should allow for partial filling or overflows when assessing both water use and effluent disposal.

Recording the information

It's very important to keep accurate records on a water use chart or on a spreadsheet.

Recording quantities and costs data on a worksheet will help you to identify where you can save water and cut costs - see how to use your water monitoring information to save money.

Finishing the water balance

With all the information you now have you can complete your water balance. You may find it easier to split up the block diagram into different processes. The water balance should show:

• all known inflow points
• all known outflow points - whether as wastewater, liquid waste, product or evaporation
• amounts of these flows

In theory, the amount going in should be the same as that leaving, although this is rarely the case. You should, however, aim for an initial accuracy of plus or minus 10 per cent of the total water quantity you can account for.

It's also important to look for inconsistencies because these may indicate leaks, unauthorised, excessive or unnecessary uses or simply something that you have counted twice or missed altogether. Make sure meters are checked regularly and properly maintained, and that staff know how to use them.

Benchmarking is a tool that can help you to improve your processes, products and services by comparing your business' performance with that of similar organisations. It can help you to identify processes that you can adopt to reduce your business' use of water and cut costs.

There are different approaches to benchmarking. Quantitative benchmarking involves detailed measurements and requires investment in research and manpower. Qualitative benchmarking, which focuses on identifying good business practice, is used to consider a specific process (such as purchasing or logistics), business performance (such as service delivery) or strategies. You should tailor the process to suit your particular business needs and objectives.

An important element in benchmarking is the identification and use of key performance indicators (KPIs). KPIs are factors you can use to measure the success of your business through achieving targets - see how to set environmental performance targets.

Using benchmarking to improve your business' water efficiency can often be achieved at relatively low cost, but can deliver significant benefits. The full cost of water - ie the cost of delivery, use and disposal - can be a lot higher than you realise. There are also other benefits of improving your environmental performance, such as an improved reputation - see how to improve your environmental performance.

The benchmarking process involves establishing your own performance level and measuring it against peer businesses on a like-for-like basis. To benchmark your water use, you should follow a systematic process:

• planning - decide who is going to carry out the benchmarking and agree on the objectives, criteria and businesses against which you want to benchmark
• information gathering - establish your own water use, eg by using a water balance, record that of similar businesses using the same measurement criteria and then collate the findings so that you can make comparisons
• analysis - review the information you have gathered, find and fill any gaps, ensure that comparisons are realistic and identify opportunities for improvement
• implementation - make an action plan consisting of quick wins and longer-term initiatives, assign responsibilities and put the plan into action, making sure that it is properly monitored
• evaluation and review - benchmarking is a process of continual improvement so you should review the results of your action plan and repeat the benchmarking exercise regularly to see what further improvements you can make

You can find data on other businesses using government sources, trade associations and trade publications. It is also worth approaching comparable businesses directly, as they may also benefit from benchmarking.

Your benchmarking report should identify where water use and wastage is higher than industry averages. These should then point to potential savings.

Once you have completed your water balance and compared your water use against other businesses, you should look at how you can reduce your water use and waste production. For example, you can do this by:

• setting targets to reduce water use
• raising staff awareness
• improving maintenance
• reviewing processes

You should have an action plan that includes processes and procedures for implementing improvements. Many of these may involve little or no cost, for example ensuring that staff turn off taps after use. Others may involve some investment but deliver greater, longer-term savings, for example water efficient equipment and technologies. It's important to monitor the implementation and results of your plan, and you should be able to adapt your plan if circumstances change.

For more information, see our guides on how to save water at industrial premises, save water at commercial premises and water reviews, policies and action plans.

You should review your water balance with senior managers and look particularly at areas where use and costs are highest. Look at whether you can change your processes or systems to make savings. Consider how easy it is to modify manufacturing techniques or products to reduce water use or effluent production.

Continual improvement

Although your water balance should enable you to make immediate savings, you should look for more savings into the future. You can achieve this through a process of continual improvement by:

• regularly monitoring processes and systems to ensure your information is still accurate
• recording costs and use by regularly reading meters
• gathering more detailed information if you see the need to do so
• constantly looking at ways of improving both the speed and quality of the data you gather
• updating your water balance charts and diagrams regularly, and conducting periodic reviews

As you become more familiar with the process, your water balance will become more accurate. This will point you towards more areas where water use can be reduced and savings achieved.

You should also benchmark your water use regularly to ensure that your business is keeping up with similar organisations.

A water balance is a management tool that can be used to show where water enters and leaves your business, and how it's used in between. It provides a way of gathering and presenting information about water use that can help you to:

• understand and manage your water and wastewater more efficiently
• work out where you can cut water and water treatment costs
• detect leaks

Developing a water balance is a straightforward step-by-step process that involves:

• gaining the full commitment of senior management - see making the case for environmental improvements
• conducting a preliminary review - see initial analysis of your water use and disposal
• drawing a diagram of your site, showing the main water inflows and outflows - see make a diagram of your business' water use
• adding the detail and making a water-use spreadsheet - see how to finalise the detail of your water balance and quantify and record your water use
• using the water balance to save money on water use and disposal - see the page in this guide on how to use your water monitoring information to save money

You should make sure you review and update the water balance regularly.

The first step to creating your water balance is to form a broad-brush picture of your water use and disposal. You should find that there is plenty of information available, as well as observations by people who work in your business. You can:

• gather information about your water use from sources such as water meters, bills from Northern Ireland Water, data from flow-meters (if you use them) and machine data
• tell your colleagues, departmental managers and employees what you are doing, and find out their views on current practices
• try to fill in any gaps in your analysis - an overnight or weekend test using your water meters might show that you have a hidden water leak

The amount of detail you need will depend to some extent on your business - for example if you manufacture products that use a lot of water, you'll need more detail. However, even if your business uses relatively little water you will benefit from a detailed analysis of use and disposal.

Once you have gathered all of the initial information together for your water balance, you can make a plan of your worksite, showing where water is used and disposed of. You should include the position of water meters and flow meters, and remember to include locations where there is a high level of evaporation, such as heating systems or laundry rooms.

If you manufacture products that include water, include those in your diagram. You are looking at the major activities that use water in your business, so you need to identify where:

• water comes in
• there is a function and a use of water
• water or waste leaves the site

Your drawing will give you the overall picture, and may enable you to identify quick wins where you can make immediate savings for relatively little cost.

In a block diagram, each major activity is represented by a box with a list of the major water uses and an arrow showing the source of the water and how it is disposed of. You can put water inputs in a list at the top of the diagram with outputs at the bottom.

Use the same units throughout - for example cubic metres per day or week - and try to make as complete a picture as you can, using the information you have gathered from the initial review. You might not be able to account for all of your water use, but you may be able to fill in gaps by adding detail to your water balance by carrying out more measurement and investigation - see how to finalise the detail of your water balance.

Your initial water balance may have identified less than 80 per cent of your water use. Depending on how much water you use, it could be cost-effective to increase this to 95 per cent. You can do this by:

• working out which activities and processes use the most water
• measuring flows to obtain more detail
• continuing to review and measure until it is no longer cost-effective to do so

Identify water supplies

Find out where your water comes from and how it is treated and distributed on-site including:

• how it's supplied, eg mains, river water, reservoir or borehole
• how it's stored, eg in tanks or lagoons, and the capacity
• whether water is treated on-site and how
• how water is transferred, eg by pump, gravity or manually

Investigate water use

Use one or more of the following to look into water use:

• walking around the site to find where water is used
• looking at location and numbers of water meters
• talking to staff about where water is used
• tracing water-supply pipes from sources to use point, if possible
• finding drawings of the water supply system

You also need to gather information such as:

• number of employees on-site or per shift
• type of product being produced
• number of lines operating
• processes such as rinses and washing cycles

Making a plan as you go along can help you to keep track of where you are, particularly if there is no diagram of the water supply and distribution system.

Identify effluent sources

To identify sources and effluent (liquid waste) disposal methods, you should:

• look at plans of your effluent drainage, surface water drainage and foul sewer systems - if these don't exist, make your own diagrams
• mark the location of any effluent meters or sampling points
• walk around the site looking for sources of effluent and wastewater
• talk to staff to get their input
• include any liquid wastes and slurries taken off site by tankers

Other water losses

Look at other ways in which water leaves your site:

• in your products - eg in drinks manufacture
• in steam, during product manufacturing or processing - such as laundries or some food processing

You will need this information to complete your water balance.

Having created the water balance, you need to quantify and measure each element. Put all major water uses and effluent (liquid waste) sources in order and, starting with the largest, work out quantity and frequency of use.

There are various ways of measuring water use:

• water meters
• flow meters
• calculations from manufacturers' brochures or handbooks
• estimates based on your knowledge of the process
• timing how long it takes to fill a container of a known volume

To measure effluent, you can use similar methods, although in some cases - for example washrooms or rinse processes - effluent flow may often be the same as water use. If waste is collected by an outside contractor, they should be able to provide data.

You should allow for partial filling or overflows when assessing both water use and effluent disposal.

Recording the information

It's very important to keep accurate records on a water use chart or on a spreadsheet.

Recording quantities and costs data on a worksheet will help you to identify where you can save water and cut costs - see how to use your water monitoring information to save money.

Finishing the water balance

With all the information you now have you can complete your water balance. You may find it easier to split up the block diagram into different processes. The water balance should show:

• all known inflow points
• all known outflow points - whether as wastewater, liquid waste, product or evaporation
• amounts of these flows

In theory, the amount going in should be the same as that leaving, although this is rarely the case. You should, however, aim for an initial accuracy of plus or minus 10 per cent of the total water quantity you can account for.

It's also important to look for inconsistencies because these may indicate leaks, unauthorised, excessive or unnecessary uses or simply something that you have counted twice or missed altogether. Make sure meters are checked regularly and properly maintained, and that staff know how to use them.

Benchmarking is a tool that can help you to improve your processes, products and services by comparing your business' performance with that of similar organisations. It can help you to identify processes that you can adopt to reduce your business' use of water and cut costs.

There are different approaches to benchmarking. Quantitative benchmarking involves detailed measurements and requires investment in research and manpower. Qualitative benchmarking, which focuses on identifying good business practice, is used to consider a specific process (such as purchasing or logistics), business performance (such as service delivery) or strategies. You should tailor the process to suit your particular business needs and objectives.

An important element in benchmarking is the identification and use of key performance indicators (KPIs). KPIs are factors you can use to measure the success of your business through achieving targets - see how to set environmental performance targets.

Using benchmarking to improve your business' water efficiency can often be achieved at relatively low cost, but can deliver significant benefits. The full cost of water - ie the cost of delivery, use and disposal - can be a lot higher than you realise. There are also other benefits of improving your environmental performance, such as an improved reputation - see how to improve your environmental performance.

The benchmarking process involves establishing your own performance level and measuring it against peer businesses on a like-for-like basis. To benchmark your water use, you should follow a systematic process:

• planning - decide who is going to carry out the benchmarking and agree on the objectives, criteria and businesses against which you want to benchmark
• information gathering - establish your own water use, eg by using a water balance, record that of similar businesses using the same measurement criteria and then collate the findings so that you can make comparisons
• analysis - review the information you have gathered, find and fill any gaps, ensure that comparisons are realistic and identify opportunities for improvement
• implementation - make an action plan consisting of quick wins and longer-term initiatives, assign responsibilities and put the plan into action, making sure that it is properly monitored
• evaluation and review - benchmarking is a process of continual improvement so you should review the results of your action plan and repeat the benchmarking exercise regularly to see what further improvements you can make

You can find data on other businesses using government sources, trade associations and trade publications. It is also worth approaching comparable businesses directly, as they may also benefit from benchmarking.

Your benchmarking report should identify where water use and wastage is higher than industry averages. These should then point to potential savings.

Once you have completed your water balance and compared your water use against other businesses, you should look at how you can reduce your water use and waste production. For example, you can do this by:

• setting targets to reduce water use
• raising staff awareness
• improving maintenance
• reviewing processes

You should have an action plan that includes processes and procedures for implementing improvements. Many of these may involve little or no cost, for example ensuring that staff turn off taps after use. Others may involve some investment but deliver greater, longer-term savings, for example water efficient equipment and technologies. It's important to monitor the implementation and results of your plan, and you should be able to adapt your plan if circumstances change.

For more information, see our guides on how to save water at industrial premises, save water at commercial premises and water reviews, policies and action plans.

You should review your water balance with senior managers and look particularly at areas where use and costs are highest. Look at whether you can change your processes or systems to make savings. Consider how easy it is to modify manufacturing techniques or products to reduce water use or effluent production.

Continual improvement

Although your water balance should enable you to make immediate savings, you should look for more savings into the future. You can achieve this through a process of continual improvement by:

• regularly monitoring processes and systems to ensure your information is still accurate
• recording costs and use by regularly reading meters
• gathering more detailed information if you see the need to do so
• constantly looking at ways of improving both the speed and quality of the data you gather
• updating your water balance charts and diagrams regularly, and conducting periodic reviews

As you become more familiar with the process, your water balance will become more accurate. This will point you towards more areas where water use can be reduced and savings achieved.

You should also benchmark your water use regularly to ensure that your business is keeping up with similar organisations.