Project Appreciation and Objectives
With domestic meter penetration increasing, it is important that domestic meter replacement strategies should be underpinned by a good understanding of meter deterioration and failure.
In 2004 WRc carried out a study into the long term performance of 12 year old customer meters. This study built on previous studies so that we now have data on meter performance covering 5, 8 and 12 years in service. The 2004 study demonstrated that meters of up to 12 years old showed a gradual under-registration and increased failure rates as meters aged. From this a method of predicting meter performance/failure using regression and probabilistic analysis was developed.
In these previous studies it was clear that the majority of ageing domestic meters stock in the UK were Class D rotary piston meters and these meters appear to age in a consistent manner.
Recent, but limited evidence, from a number of meter managers has identified that some newer 5 year old meters (i.e. meters installed in 2001 and tested in 2006) have quite different performance characteristics, with a higher degree of meter under-registration. The reasons for this apparent difference in performance are not understood and there are a range of possible explanations, including: different manufacturing practices, different materials of construction, or an unrepresentative sample of meters.
This project tested a representative sample of 'newer' meters that had been installed for about 5 years and compared the results with the previous studies to identify whether there had been a change in the long term performance characteristics. Conclusions were then be drawn on the potential implications for meter under-registration assessments and meter replacement strategies over the next AMP period.
Benefits to Clients
- Better informed decisions on meter replacement strategies.
- Improved accuracy of consumption assessments based on newer technology meters, that have been installed over the last 5 years.
- Updated evidence to justify domestic meter replacement policies.
- Greater confidence in the meter replacement strategies for the next AMP period.
This project followed the methodology established in previous studies, with a statistically representative sample of meters being obtained and tested. Resultant meter error curves were combined with consumption profiles to obtain a figure representative of the overall deterioration in performance. Meters were categorised into performance groups to obtain the distribution of errors in the sample. Failed meters were examined to investigate modes of failure. Data were combined with previous studies to show meter performance deterioration over time.
- A report detailing 5 year old domestic meter performance compared with previous studies. Results included categorisation of performance plus modes/rates of failure.
- A workshop to disseminate results and discuss implications on revenue, water balance calculations and meter replacement strategies.
Related WRc Work
- Water metering benchmarking study. WRc, 2005.
- CP138 New technology meters. WRc, 2004
- CP188 The long term performance of domestic water meters. WRc, 2004.
- Collaborative project - Long term performance of meters. WRc, 1998.
- Comparisons of Class D & Class C meter performance. UKWIR, 1996.