Generally, water is more on hard water. This builds up scale deposits, which is what hose stains are all about. Here are a few ways of dealing with this problem:

1. Do not allow your utensils, particularly glassware, to air dry. Wipe them dry as soon as possible with a lint free dish towel or use paper towels.

2. To remove water stains. Rub gently with a non abrasive cleanser, rinse and dry as above mentioned.

3. You could also soak your plastic ware in a basin filled with a mixture of warm water and white vinegar. You can leave them there for a couple of hours, though overnight is preferable. Wash, rinse and dry.