How long will it take to lose 15-20 pounds by running?

being female 3-4 pounds a week. Mix up your workouts. Try speed intervals and other sports.

water is your best friend.
Greens and healthy protein, you are not eating enough calories.

You're building muscle, and may gain weight before you lose any. 5 miles a day (unless you're used to this) is a lot to start with. Try half a mile and increase it each week by another half mile. 15-20 lbs it will take until around November of 2015 if you do this everyday.

most people that actually do it right lose about 2 lbs a week. soooo 7-9 weeks