You must tone your facial skin to adjust the pH every time your skin is exposed to tap water. The reason is that tap water is highly alkaline, as high as 9.3 in the San Francisco Bay Area and even higher in mineral rich areas of the world. While high alkaline water might be nice internally, external exposure is one of the most damaging things you can do to your skin.
When your skin is too alkaline, the fatty acids are depleted and your skin feels dusty and dry. Depending on your genetics your skin may either not replenish the fatty acids (oil) and your skin will stay dry or it will produce extra Sebum (naturally occurring oil in the skin) to compensate giving you oily or combination skin.
The solution is so very simple.
Apply a low pH (low 6's high 5's) toner after rinsing your face. It is important that your facial toner is alcohol free and astringent free. Be careful of herbal astringents like Witch Hazel as well as the synthetic varieties, none of them have any justified place in your facial toners.
Think about it. Your cleanse your face with a wonderful cleanser and then rinse. And while it is important to readjust the pH of your skin, why would you wish to apply an alcohol or astringent toner designed to tighten and close up your skin before you apply your serum and moisturizer. You want your serum and moisturizer to penetrate easily and deeply. Alcohol and astringent based toners are a brilliant deception perpetuated both by the commercial skincare industry, and sadly many on the natural side of the industry still find this a confusing concept and continue to follow suit in step with commercial skincare's conventional wisdom.
So don't skip your toner. And if you want a really good one, find one with a low pH and a natural anti-inflammatory like Rosewater.