I have a problem with my toilet and tub yet I do not have issues with my sinks in the bathroom or in the kitchen.
I have only one bathroom which was working for 4 months after a handyman replaced the cast iron pipes with ABS.
I went down the crawl space and saw that he forgot to put a vent for the toilet. There is one for the tub and a seperate for the double sinks.
I snake the toilet pipes after taking the toilet out and I still could see the water inches below the floor. If