They sell bacteria killing additives for humidifiers / dehumidifiers for a reason. I sure would not drink the water from a dehumidifier.
I tested the PH on my sump pump water thinking it is rain water...Still high and needed adjustment (since I live next to a farm field, who knows what chemical run off is also in it). I also tested captured rain water and it was high and needed adjustment.
Some say they use straight captured rain water as is like mother nature meant plants to get but it looks like I live in an area where any water source for me will need PH down adjustments.
PS..If I remember right, PH neutral is 7 and I think that is still high for soil and hydro...buy I just learning also.