The water in the spare bathroom toilet syphons away, if it is not used on a daily basis. This toilet was just replaced last month and has the problem since then. Please advise as to what the problem might be. Thanx
This may sound simplistic, but the whole reason systems are designed with vent stacks are so that a siphon situation isn’t created. I would initially be suspect of the specific vent for this toilet. Sometimes rodents/birds build nests or just fall into roof stacks and create a clog. If you can get on the roof with a flashlight you may be able to confirm. Otherwise, pull off toilet and run snake up stack from that piont- can be a messy job. Good luck.