Jeff767

There is no requirement to land because the toilets stop working. It’s simply a matter of common sense and time remaining to the scheduled landing. It’s also not an emergency. Both Boeing and Airbus toilet systems using vacuum flushing can be finicky however the single biggest reason for a failure of all toilets is they were not dumped prior to the flight. Once the holding tanks reach a set level the system shuts down. Airbus toilets due use some water on each flush to help clean the bowl. The toilet will operate without water but what happens now and then is the toilet water flush sticks open and continuously dumps water into the bowl. The result is the aircraft water tanks go empty and the lavs on that circuit shutdown because the holding tank fills up. Boeing and Airbus have two separate lavs circuits on long haul aircraft to insure an issue with one leaves the other half of the toilets operating unless of course as mentioned they were never dumped in the first place!