Hi
Since you already have an injunction for easement rights(right of passage), you can submit an Interlocutory application asking for permission for replacement of old water pipeline with new water pipe line and take permission from the court.
In the Interlocutory application, you need to additionally add PWD as the respondent and ask the court to direct PWD to replace the old water pipeline connection with new water pipeline connection.
Courts will definitely oblige on the grounds that right of air, water, light are unfettered rights and these cannot be blocked by the neighbours on any grounds whatsoever.
Hope this information is useful.