The main question concerning WSP (Water Safety Plan) is generally, how much money shall be provided for this purpose from the budget. To give a correct answer, one has to be in the position to compare all issues which need financing. To be able to allocate money according to real need, a proper risk analysis should be carried out for all the processes within the company.
This kind of analysis can be the base for the implementation of WSP according to principles of process development.
My references are Hungarian Waterworks.