TV time for toddler

GirlMom💗 • 2015 👧🏼 2017 👼🏼👼🏼 2018 👧🏼 🌈 2020
I babysit a set of twins. They have oodles of toys in the living room, but aren't ever interested really. They are two years old, still sucking on pacifiers, don't talk hardly at all and their parents just let them watch cartoons all day. They haven't started working with them on potty training or anything. Their never let outside by the sounds of it. They have a huge dog so the backyard is consumed with dog 💩. Front yard is close to street! 
I always take their pacifiers away from them. Today, I am watching them and am not letting them watch their TV shows. What do you think is an acceptable time in front of the TV?