The United States Geological Survey estimates that (as of 2005, the most recent year for which data is available) we withdraw 410 billion gallons of water a day, including both fresh and saline water. Most (80%) of these withdrawals go to thermoelectric power plants (for cooling) and agriculture (for watering crops).
Level 2 is the second darkest hair color level. It is usually used to describe a natural black, and is the natural color of most people who have naturally black hair along with Level 3, soft/light black hair. Refer to the hair color chart. Most drugstore black hair shades are Level 2, medium black. Level 2 hair color is best suited to people whose natural hair color is between Level 2 and Level 3.5.
This could be tested by using litmus paper to gauge the pH level of these salon products, and comparing the pH levels with the established natural level of 5 for hair. (Hair and skin actually have a pH that ranges from 4.5 to 5.5, and is typically averaged to 5.0.) You could test a number of salon products (shampoos and conditioners) and a number of store brand versions.