If you notice "white" or cloudy tap water in California, it is almost always caused by tiny air bubbles trapped in the pipes, a phenomenon known as "entrained air." This often happens when air enters the water system through a recent repair or when cold water travels through a warm building, causing the dissolved air to be released as the water pressure drops at the faucet. Because California relies heavily on groundwater from deep wells (roughly 70% in many regions), the water is often under high pressure; when it hits your glass, the air escapes, creating a milky appearance. You can test this by letting a glass of water sit for a minute: if the whiteness clears from the bottom up, it is just air and perfectly safe to drink. While California water is often "hard" due to high mineral content (calcium and magnesium), those minerals typically don't turn the water white unless they have crystallized into scale, which would look like white flakes rather than a cloudy liquid.