Metropolitans' Water Supply Report

Part D: General Mineral and Physical Analysis 

The transportation of water through natural waterways and aqueducts across the state results in significant evaporation, ultimately elevating water hardness. Water is deemed “hard” when it contains high levels of calcium and magnesium; however, it remains safe for customers to drink and use. Rainbow Water receives a blend of water sourced from the SWP and Colorado River through pipelines connecting to the Robert A. Skinner Treatment Plant in Temecula.

The water blend percentage from SWP and Colorado River varies and estimated to have an average 228 parts per million of total hardness. Water softeners installed by the customer can reduce the mineral content, though this process does not offer any direct health advantages.  The information and data in  Metropolitan Water District of Southern California's Table D report includes the general mineral and physical analysis of each water source. The cornerstone of the water quality report is a table that lists the results of year-round monitoring for nearly 400 constituents and the list includes data for all reported constituents.  Metropolitan met all primary drinking water standards in 2020.

The table lists the quantity of a constituent, meausred range and averages in Metropolitan’s water and comparison of the allowable state and federal limits. 

Reports are published upon receipt from Metropolitan (two to three months after sample is completed).
 

Part D Reports