Simulation of lead compliance data

Lead in drinking water principally arises from contact between municipally supplied water and lead service pipes. Compliance sampling which is used to assess lead levels on a routine basis usually incurs a wide variability. This is due to the large number of random factors which effect it. A simulation programme has been written to mimic the sampling process, the variability in water quality, differences in the housing stock, and customer characteristics. Comparison is made in one case between the predicted and observed distribution of lead levels and found to be in good agreement. The analysis shows that for water with low alkalinity, fluctuations in water quality are a significant contributor to variability. The simulation programme is used to assess the significance of different performance measures, the impact of different measurement methods, and different lead strategies on lead exposure. The impact of sample size and the number of leaded properties in a compliance zone is analysed and discussed.