• Well water usually isn't much better than tap water. While its chemical compositon may be more consistent, it is usually extremely high in mineral content.
   
• The heat buildup associated with longer press runs intensifies the chemical imbalance problems associated with tap water.

Fountain Solution Water Source

Many dampening problems begin right at the faucet.
Here's how eliminate one problematic variable

The best choice of a water source when mixing fountain solutions is bottled distilled water (not spring water). Tap water may be convenient, but it is inherently inconsistent in terms of hardness, conductivity, and pH. This minor extra expense will repay itself in improved print quality and pressroom productivity.

The problem with tap water is that it is usually high in mineral content, namely iron, calcium, and magnesium. These elements tend to become deposited on the plate surface and interfere with the chemical balance of the dampening process. Additionally, the chlorine added by most treatment plants can react with the compounds in the fountain solution chemistry to form hydrochloric acid. This acid can dissolve the desensitizing coating on the printing plate causing scumming and toning.

Compounding this problem of unwanted chlorine and mineral content is the fluctuation in concentration. Rainfall, bacteria count, and other mitigating factors can and do affect the levels present at any one time. It is very difficult if not impossible to maintain consistent dampening performance while attempting to counterbalance the effects of these variables.

Save yourself a headache. Buy distilled water instead.