These early 707's with JT3C engines that used de-mineralized water for thrust augmentation were operated along side DC6's and Convair 440's that used ADI.
The service bulletin was initiated so that the 707 aircraft could be operated with ADI if no demineralized water was available or, had been incorrectly filled with ADI fluid...ground crews being what they usually are...inattentive.
Usually, the 707 aircraft that used ADI instead of de-mineralized water required a compressor wash at the minimum, as the compressor blades were subject to severe corrosion IF
a water/methanol mix was used.
READ the manual...when all else fails.
Something most folks fail to do...until its too late.