Our master bath toilet has a low water level and will gurgle when flushed. Soon after noticing this we realized the half bath toilet is doing the same thing. They are both tankless toilets on the first floor of our home. The upstairs toilet is a standard toilet and is not having any issues. Although it feeds into the main sewage line from another direction, so a clog wouldn't likely effect it. We tried a few methods to remove the potential clog (plunger, auger, dish soap and hot water) and it seemed to help, but they're both having the same problems again. Things to note- we are on a septic system, the water level in the tank will at times rise when the nearest sink is turned on, the house was just built in May of 2019, although the septic tank was here from the previous home. Any suggestions on what the problem could be or how to fix it would be appreciated.