(1) The Approving Authority may allow use of shared systems for upgrade of existing systems or to serve two or more facilities that will result from division of a Facility without granting a variance pursuant to 310 CMR 15.410 through 15.413 only where:

1. (a) the proposed shared system satisfies all technical requirements of 310 CMR 15.100 through 15.292 without the need for a variance except setbacks from property lines between facilities served by the shared system;
2. (b) there will be no new construction or increase in design flow from the facility or facilities to be served by the shared system;
3. (c) the applicant proposes institutional arrangements as described in 310 CMR 15.290(2)(c), and records a Grant of Title 5 Covenant and Easement essentially identical to that contained in 310 CMR 15.000: Appendix 1, in accordance with 310 CMR 15.290(2)(e); and
4. (d) the applicant provides the Approving Authority with the insurance policy or other comparable financial assurance mechanism required pursuant to 310 CMR 15.290(2)(d).