I have a family with pit bulls next door to me at the RV park I stay at while working in the oil patch. They have a male, female and a pup from her litter. The male is young, big, full of testosterone, and overall nasty. They put up a five-foot high metal fence anchored with steel driven fence posts and anchored further to the three foot chain link fence separating lots in the RV Park. The hose faucet to my RV is located next to the fence and each time I turn it on or off he attacks the fence trying to get at me.
A couple of months ago, the woman had a baby who is too young yet to be outdoors. Given the attitude of the male pit bull, I worry what might happen when their youngster becomes a toddler. Even though the dog may consider him/her family, they can be unpredictable if something or someone excites them and that anger happens to transfer to a tyke who may be in the yard. The above story is another example of that type of typical behavior of that breed.
I believe you have very serious cause for concern, for yourself, for the baby, for other persons and animals in the area, and for the mother of the baby.
You may wish to video the situation with the dog while you are getting water. Burn a dvd, mail and/or email the park owner. Keep a copy. Talk to the manager and write a letter to the park owner or office or corporation.
I do not know how much information you have on pit bulls and their dangers and history of attacks, but here is a start:
https://www.nationalpitbullvictimawareness.org/
http://www.animals24-7.org/2017/08/08/pit-stop-archive/
and you may wish to look at youtube: “pit bulls jumping fences”, plus much information has been posted here on FR, keyword “pit bull”.
My neighbor behind me has a still growing pitbull that gets aggressive every time I go in the back yard. Right now, only a three foot chain length fence separates us. My old 6 foot fence was old and rotten, so I took it down with my last neighbor, but I am planning to put it back up this month.
I have 2 labs and I can see this pit coming over the fence to attack them soon. Its either a new fence or anti-freeze hotdogs for the pit.