A water balance is a numerical account of where water enters and leaves your business, and where it is used within the business. Typically, the balance contains information about the amount of water used by each main process. It is based on a single, simple concept that what goes in must come out ... somewhere.

Follow the simple six-step procedure outlined here to construct a water balance for your business. It will help you to understand and manage water use and effluent production across the site. It can also help you to identify the areas that offer the greatest opportunities for cost savings and highlight possible leaks - setting you on your way to significant cost savings by reducing water use.

(N.B. this section is based on information from Good Practice Guide GG152R Tracking water use to cut costs.)

STEP 1: Obtaining top-level commitment and assessing resources required

The wide-ranging nature of waste minimisation - product design, purchasing, operations, engineering, distribution, finance, etc - means that it is essential to obtain the broad support of the whole management team.

One way of encouraging senior management support is to develop performance measures which are reported regularly to the Board or another management level. These measures provide a link between performance and the waste minimisation programme. Actions such as this also help to emphasise the importance of waste minimisation and to integrate it into normal business operation.

For more details see Getting Senior Management Commitment, or contact the Envirowise Advice Line.

STEP 2: Preliminary review

Gather relevant data, such as water bills, meter readings and flow data - aim to account for at least 80% of the water you pay for. Look for any gaps in your data that may cause a problem. At this stage, you also need to decide how detailed the water balance needs to be - it must be a cost-effective exercise.

For more details see Section 2.2 of GG152R Tracking water use to cut costs.

STEP 3: Drawing the picture

Sketch your site or produce a flow diagram on which you can include all areas that use water. Note the location of any water meters and the discharge points for domestic wastewater and trade effluent. Mark on all the areas/processes that use water. Walk around the site whilst you carry out this exercise - you may discover unknown or unnecessary water use, such as leaking taps or pipes, or hoses that have been left running.

For more details see Section 2.3 of GG152R Tracking water use to cut costs.

STEP 4: Adding the detail

For each process/area that uses water, identify the source of water used, eg mains supply, extracted from surface waters, pumped from a borehole. Similarly, for each stream of wastewater, identify the drainage system to which it is discharged. Highlight the processes/areas that are large users of water, or perhaps use water with an increased value, such as steam or treated water softened, demineralised, chlorinated, etc. You then need to quantify and record the water use and effluent flows in appropriate units, and calculate the associated costs.

For more details see Section 2.4 of GG152R Tracking water use to cut costs.

STEP 5: Using the water balance to save money

Now that you have a better understanding of your water use and effluent production, look for areas where water savings can be made.

Use the water balance to rank processes/areas according to the volume of water used or effluent generated, and look for use of high grade water - these are likely to offer the most opportunities for making savings. Use the cost data to identify processes/areas where water savings are most likely to result in short payback periods.

For each stream ask yourself the following questions:

  • Is the water use necessary?
  • Could less water be used?
  • Could water be re-used or recycled?

For more details see Section 2.5 of GG152R Tracking water use to cut costs.

STEP 6: Continuous improvement

Schedule in a review of your first water balance, perhaps in three to six months' time. Regular reviews and updates will allow you to monitor progress, adjust targets, or include other water saving measures into your action plans because of changes in technology, cost or legislation.

For more details see Section 2.6 of GG152R Tracking water use to cut costs.