Prediction of Septic-System Failures

In response to EPA requirements to conduct a cost-effective analysis for on-site wastewater disposal systems, a computer model was developed that predicts the number and temporal distribution of single-family residential septic system failures. The model was calibrated with 10 yr of data and verified with another 10 yr of data on septic system failures in Acton, Mass. The expected median life expectancy of septic systems in Acton was within the range determined in the study of another New England community. The model predicts the expected number of failures for each of the next 20 yr and can be used as input for presenting worth calculations, estimating sanitarian work loads, and predicting water quality.