Alas, we currently only require a 1% slope on the SBS and SBD. This means BWVs attract solids (as there is insufficient slope to move them through) which means high risk of failure if they are not cleaned constantly.  Cleaning a BWV properly requires the removal of 12 bolts and vigorous scrubbing. I know, in installed one at my house just to see. It is very unlikely that residents will be prepared to do this.

 

NORTON RECOMMENDATION:

Required a 2% slope on the SBS and SBD.