The main thing that will affect the drying rate will be the relative humidity where Zack is. The moisture content in the air exerts a pressure to keep the pipe damp or let it dry. After that will be temperature, higher temperature, laying in the sun, again, raises capacity for how much moisture the air can hold, so, faster drying. Maybe Zack can record the average temp and humidity during the drying period, but unless he lives in Arizona, I am guessing a couple of weeks to totally dry.