Beyond PCC – Water Diary Mini Research Project (2020)

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  • Introduction
  • What is it? It stands for Per Capita Consumption.
  • What does that mean? How much water a single person uses per day.
  • How is it measured? Using a water meter, the total use per day is divided by the amount of people who live there.
  • How is it reported? Welsh and English water companies report to Ofwat, and in AMP 7 water companies have regulatory targets to reduce PCC by around 6%.

PCC is calculated by metering a house and dividing water use by the number of residents. There are two main limitations to this measurement: 

  • Water companies don’t always have accurate information of how many people live in a home.
  • We use water in many locations every day, not just at home, and PCC doesn’t account for this, yet we often talk about it as if it is ALL the water we use in a day.

We wanted to find out how much extra water we use outside of the home.

We asked Waterwise Supporters, Twitter followers and friends and family to complete a 2 week water diary – recording all water they used outside of their homes. We had 40 responses, which we considered a reasonable sample size for the purposes of this small research project. Although some of the participants might be considered relatively more ‘water aware’ than the average UK resident, our results offer an insight into how much water people are using outside of their homes..

We emailed a digital copy or gave people a hard copy of the water diary. We encouraged people to print it and fill it in day by day. Once the diaries were collected we had to make some assumptions about how much water each appliance used. For example, our participants had told us how many times they’d flushed the toilet but not how many litres that toilet cistern held. We used average UK figures for the purpose of this research – the assumptions can be found at the end of this document, on page 4.