Originally Posted by
jc94
Either way, the question remains how many toilets to customers are required by law to operate and how frequent is this? It seems crazy that AC have a 200%+ surplus when they could just knock out half of them and fit another 10 seats in.
Other question, were the sacrosanct J (and PY/J) washrooms open to all pax?

I just did some research, this is the two most useful sources I found:
1.
https://www.airliners.net/forum/viewtopic.php?t=459195
Basically, there is no rule or regulation.
2.
https://en.wikipedia.org/wiki/Aircraft_lavatory
The normally accepted ratio is 50 to 1, but this is not a rule. However, it mentions that aircraft missing ashtray is not allowed to carry passengers (2011 Jazz flight from YFC to YYZ)..