Waterwise on the Farm (Version 2)

Step 3: Calculate how much water you should be using

When you know how much water you are using, the next step is to work out how efficiently you are using it.

Using Forms 1, 2a and 2b, compare your expected use to your actual use. If your actual use is more than 10 per cent greater than your expected use, this indicates that you are using water inefficiently. Even if the difference is less than 10 per cent, it is still worth checking regularly how much water you use and following the water efficiency activities in the next chapter to carry on using water efficiently.

If your expected water-use is less than your actual water-use, it may be that:

  • your meter is over-recording how much you are using;
  • you have underestimated how much water your animals or crops need.

Case Study

Water Efficiency Awards Commendation: JR Weekes & Sons
Mr Weekes and his sons, who run a dairy farm in South Wales, have introduced several measures designed to improve overall water efficiency and reduce wastage. Isolation valves are installed in each leg of the pipework that supplies the animal drinking troughs. The legs are drained and inspected during the winter. All pipework above ground is lagged to protect against bursts and leakage in winter, and all visible pipes and troughs are inspected daily for leakage.

Comparing the difference

To compare the percentage difference between your expected and your actual water-use, you need to subtract the total theoretical water-use (from Forms 2a and 2b) from the actual water-use (Form 1) to get the difference between the two. Donít forget to convert the totals into the same units before you start (conversion factors are given in Table 3). Then divide the result by your total theoretical water-use (Forms 2a and 2b) and multiply by 100 to get the percentage difference between your actual and your theoretical water-use.

Percentage difference = (total Form 1 - (sum of totals on forms 2a and 2b) x 100) / Sum of totals on forms 2a and 2b

e.g. (10,000 - (5,000 + 3,000) x 100) / 8000 = 25% more water being used than would be expected

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