SmartMeter – helping to cut water bills

Intelligent water meters help indentify supply pipe leakage. Severn Trent Service's Fran House provides an update on how the trials of its SmartMeter C100R are progressing. Supply pipe leakage has always been difficult to accurately estimate due to its irregular occurrence and relatively low flow rate levels, but the impact of incorrectly assessing the scale of the problem can be wide-reaching.

Continuing to use current technology and data collection methods is no longer a sufficient option for companies to supply credible, auditable and accurate data to OFWAT in the yearly return.

Designed and trialled by seven UK water companies and manufactured by Severn Trent Metering Services, the revolutionary SmartMeter(tm) C100R water meter has been developed.

This will assist in water saving, by enabling effective leakage management and supporting the application of complex tariffs to curb demand.

The meter is ideally suited to address recent water shortages in particularly water stressed areas where below average rainfall and increasing summer consumption have combined to seriously affect water resourcing strategy.

The C100R was launched in July 2006 at the Global Smart Metering for Water Conference in London.

When designing the meter, an important requirement was the ability to differentiate between leakage and legitimate use to assist in billing and prioritisation of supply pipe leak repairs.

A detailed specification was developed, which included:

  • Leakage data (location, rate, duration and date)
  • The need for varied tariff application, such as monthly, time-of-day, seasonal and peak week rates
  • An efficient AMR (Automatic Meter Reading) system, including real-time data transmission for time-of-day tariff application
  • Flexibility in the data collection method to enable migration between different reading technologies
  • Peak-week demand data (current and previous year)

Conventional wisdom in the UK water industry is that perhaps 1% of properties suffer from a leaking supply pipe at any one time.

The annual rate of replacement and repair of supply pipes is less than 0.5%. Initial findings from the C100R N1.0m3 meters installed by Severn Trent Metering Services indicate the incidence of leaks may be significantly higher, with 6.8% of meters installed to date reporting leaks of more than 24 hours in duration.

One percent of meters showed leaks that were still ongoing, which at the time of writing equates to more than 80 days.

High bills

Early data from the meters installed has also clearly identified the proportion of the consumption made up by leaks can be very high, but may not be detectable in the current systems used by the companies to protect their customers from high bills due to leakage.

This is particularly important, as only meters with excessive total consumption would be considered for a “kick-out” of the water bill, where the water company would investigate potential leaks and provide discounts accordingly.

This is regardless of whether this was caused by actual legitimate use or a supply pipe leak.

Consequently, a leak could be disguised on a single occupancy property if the metered consumption fell below that of the average house with multiple residents.

In some instances, the C100R has identified leaks that account for 50% of the water bill.

However these may well have gone undetected as the water company would be unable to predict the range of consumption without knowledge of the number of people living in the property.

Initial data from the trial shows that the ratio of leaks compared to actual water used varies significantly, but has reached as high as [a minimum of] 74% in one case.

Another significant finding showed the distribution of leaks to be weighted heavily towards the smaller size flow rates, with events up to 20 litres per hour accounting for 58% of all leaks.

Current theory on UK leakage levels is based on known data. Water companies rely on a series of means to detect leaks ranging from anomalies identified by the billing system software, local area analysis and, to some extent, guesswork.

These techniques lend themselves to identifying large leaks, but are unlikely to detect a leak below 20 litres an hour, which could equate to a dripping tap.

Over the course of a year, this could amount to as much as 175.2m3 of water that a metered customer would pay for, but would not consume.

Scarcity issues

Water shortages continue to be a major concern in the UK. The SmartMeter C100R is already proving to be a valuable tool in addressing future scarcity issues through the provision of detailed leakage data, and peak week demand information.

Initial data obtained from the meters currently installed has shown that the number of properties with leaks may be higher than estimated in the UK, and that even large leaks may be concealed in properties where low numbers of occupants are living.

More comprehensive data will be presented in the next quarterly instalment of WET News’ intelligent concentric meter diary.

Fran House is marketing manager at Severn Trent Metering Services.

T: 0121 313 2300.

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