The OSET NTP (On-site Effluent Treatment National Testing Programme) is a SWANS-SIG initiative which has evaluated the performance of 21 treatment units in Trials 3 to 8 (2007 to 2013) via a nine month testing programme in each trial. Of the 17 systems currently available commercially, all systems met the 90% performance requirements of AS/NZS 1547:2012 for biochemical oxygen demand (BOD5) and total suspended solids (TSS), but only 47% achieved 100% for both parameters. Benchmarking of 16 test results from Weeks 23 to 35 of the test programme for five chemical parameters, faecal coliforms and average daily energy use shows the relative performance for all treatment systems. These results enable a comparison of overall performance rating, treatment process stability, aeration effectiveness, nitrogen reduction and energy consumption. The ongoing success of the OSET NTP will depend on more council Funding Partners joining up to contribute grants towards management and auditing costs.