3 year old was potty trained at 2 but has regressed for the last 8 months

Hoping to get some tips I haven’t tried yet to finally stop cleaning up bodily fluids daily. My daughter (middle child) was fully potty trained when she was 2. She went several months without accidents at home or school. Then, November hit and her new baby sister was born. At this time she stayed with a family with a slightly older girl still in diapers.Since the new baby has come, my now 3 year old constantly goes to the bathroom outside the toilet. At school she uses the toilet and has no accidents. When we put her on the toilet at home she goes without fear or any issues. The issue is anytime she needs to go to the bathroom independently (only at home), she will sneak away and pee on the steps, on the floor just outside the bathroom, in her room, pretty much anywhere but the toilet. It’s so frustrating and we don’t know how to fix it.We know it’s not physical since she uses the potty at school, can use the toilet properly without assistance when we’re with her, it’s not that she’s distracted playing since she does sneak off close to the toilet but just not in it. I know regression is common with a change like a new baby but it’s been 8 months now. We’ve tried rewards, talking to her about it (doesn’t give a reason for why she does this), reading books about it, giving her a new potty seat, nothing has worked. Please help, we’re at our wits end! via /r/Parenting https://ift.tt/2PuITXa