yep, you've certainly got a 'kink' somewhere, and it sure sounds like it's part of the 'slide' and any water lines that are part of/within it. Now, that seems odd since you DO have water while on the water pump, but the incoming CITY water may hit several other points before it gets to the same place, so therefore a kink is probably the suspect.
Run the slide IN, and then see if the CITY Water still reacts the same...that might be a good indicator.
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada - Hiawassee, GA! (also, '14 Gulfstream Amerilite and '07 ForestRiver Rockwood) : )