Someone had all 3 of the toilets in their home hooked up in such a manner that, the supply lines coming from the angle stops were attached to shower diverters. The shower diverters were hooked up to the fill valves and the branches of the diverters were attached to these sprayers which looked like deck sprayers. I asked the home owner what these set ups were used for and he stated that they use them to wash their toilets.

I was sure these are illegal hook ups, confirmed same with plumbing manager and told owner that they needed an anti siphoning device attached at the right point or, that they would need to make sure that they don't invite plumbing inspectors to their parties.

Actually told him they are illegal and should be returned to a normal set up.

It if would be a legal set up, would the anti siphon device go between the fill valve and diverter or would 2 anti siphon devices be required?

Possible that these were not for spraying the toilets for cleaning them and were in fact, crude bidet set ups?

Have been thinking it over and now believe the anti siphon device ought to be between the sprayer and it's connection to the diverter.