The Impact of Lateral House Connections on the Serviceability of Sewer Systems

It remains unknown how lateral house connections affect the performance of the sewer system, since the assessment of serviceability is mainly based on the state of the main sewer system. Further insight into the contribution of lateral house connections to the overall level of service provided can aid to target investments to parts of the system where it is most effective. To this end, techniques from the reliability theory were applied to a commercial sewer maintenance database to quantify the impact of lateral house connections on the serviceability of sewer systems. Analysis of the data showed that the failures follow a Poisson distribution. A comparison of the derived failure rate with values obtained from a different study revealed that the blockage rate of lateral house connections is an order of magnitude greater than the failure rate of the dominant mechanism of main sewer systems, thereby making the impact of lateral house connections on the serviceability of sewer systems substantial.