The answer to that question is "yes and no" because the degree of hardness varies depending upon the time of year and your location within the City. Water hardness refers to the mineral content in the water and is commonly expressed in "grains" of hardness. Generally water with 10 grains or more is considered "hard." Water imported from the Colorado River and Northern California is typically hard, while the City’s well water is moderately hard. For specific hardness levels for each source, please refer to the City’s current Water Quality Report.
While the hardness of the water does not affect its safety, the higher mineral content can cause white spots on glasses in the dishwasher. The City generally uses water from the Colorado River, Northern California and local wells. Water use is alternated throughout the year. Because water is blended from a variety of sources, you may notice spotting on glassware more during the winter.
It is best to read the owner's manual for your dishwasher and follow the manufacturer's recommendations regarding settings for hard water. Some other tips that may help reduce spotting include using hotter water, varying the brand and type of rinse agent and detergent, and adding white vinegar to the rinse cycle of the dishwasher.
For more information click, on the following link.Water Hardness in Fountain Valley