What's the total volume of water in the toilet to start with? I doubt adding alcohol to make up 70% will stay in the bowl. Generally the volume is fixed in the bowl, no? It will the keep draining away!
There won't come any new water into the bowl, so sooner or later you'll reach your 70 % as long as you keep pouring alcohol into it. But you would also lose a lot of alcohol in the process. So, not very economical indeed. But I think it's well worth the effort if somebody wants to drink from the water (actually it was a joke, what a waste of perfectly good alcohol that would be ;-) ), for everybody else I'm sure there are commercial products available with more efficiency that are cheaper (and hopefully won't kill nature after it gets into the sewer, please don't just take anything).
I was thinking about the potentially pathological germs found on toilets and toilet floors, and I believe that could be very accurate if the samples were taken from public toilets. Also, the source linked on this webpage I trust the most - as it was scientifically published - even states: "The survival and environmental spread of Salmonella bacteria from domestic toilets was examined in homes, where a family member had recently suffered an attack of salmonellosis.". So no wonder they found Salmonella there.
I do not believe I have any Salmonella or Campylobacter in my personal bathroom as I don't know anybody ever infected and I'm careful with food that could be infected.
If you wonder why I'm writing all of this, I think it's pretty on topic. I had to go to the toilet and it did not really work out nicely, so I missed the early train. TMI? I'm pretty sure. :angel: ...and I didn't even have my phone with me.