Existing on-site systems is an ongoing challenge where some action under SBM was taken in terms of conversion of insanitary latrines to sanitary ones. We are pushing for ULBs to ensure new construction conforms to IS standards and TN building rules. Retrofitting of existing septic tanks has been tried by TNUSSP on a pilot basis for understanding the feasibility. This is an evolving field; we are yet to reach any conclusions. For specific queries, please write to tnussp@iihs.ac.in.
In terms of institutionalisation, we ensure that new septic tanks are built according to standards, and thereby ensured that building bye-laws are aligned towards this. Please see suggested changes to Municipal Building Rules here.
Please also see response to question number 22