The CEQA Guidelines (Sections 15162 and 15164) require that a lead agency prepare an Addendum to a previously adopted IS/MND if some changes or additions to the environmental evaluation of a project are necessary but none of the following occurs:

1. There are no substantial changes in the project which require major revisions to the IS/MND or a substantial increase in the severity of previously identified significant effects;

2. There are no substantial changes with respect to the circumstances under which the project is undertaken which require major revisions to the IS/MND; or

3. No new information of substantial importance, which could not have been known with the exercise of reasonable diligence at the time of IS/MND adoption, shows any of the following:

(i) the project will have one or more significant effects not discussed in the IS/MND,

(ii) the project will result in impacts substantially more adverse than those disclosed in the IS/MND,

(iii) mitigation measures or alternatives previously found not to be feasible would in fact be feasible and would substantially reduce one or more significant effects of the project, but the project proponent declines to adopt it, or

(iv) mitigation measures or alternatives that are considerably different from those analyzed in the IS/MND would substantially reduce one or more significant effects on the environment, but the project proponent declines to adopt it.

The purpose of this Addendum is to evaluate the new recycled water storage tank location and expanded access road improvements and to demonstrate that the new proposed location and access road improvements do not trigger any of the conditions described above; therefore, an Addendum is appropriate.