On April 15, 1968 Yuima and Palomar Mutual Water Company entered into an Agreement for Acquisition of Water System and Palomar Mutual became known as Improvement District "A" (IDA). Palomar's water system was transferred together with its rights to develop, produce and divert water which had been given to them by Rossmoyne Village, Inc. The Improvement District operates under a separate operating permit.
Yuima also became successor in interest to the Stipulated Judgment in the case of Strub vs. Palomar. That judgment limited the Palomar Mutual Water Company's service area (now known as Improvement District A) to the withdrawal of no more than 1,350 acre feet per year from the San Luis Rey River upstream of Cole Grade Road.
The Board sets a separate water rate for IDA to cover IDA’s operating expenses and its equitable share of Yuima's general and administrative expenses. All revenues received from IDA are used solely to pay IDA's expenses for operation, maintenance, and capital improvements.
IDA also includes 1,127 acres of District-owned watershed land and 31 scattered well & reservoir sites (28 operating wells).
