No way la, they are using a 1 year return rainfall in drainage design... Can't help until they update the code... Even if they update the code to 5 year return, IMO, it's still too low... You can still see flooding easily based on these extreme weather...
It all depends... In the old days cities used to have combined sewers (sanitary + storm). In small population area, that won't be a problem. But when the city grows, especially when people start talking about saving water resources and being environmentally friendly, that won't work.