I live in Minnesota and am trying to find when S traps were determined to be "illegal". Also, what is the problem with them? Thank you very much for this forum!

We too live in MN and we think we can help but need more info. Are you talking bungee cords or ratchet straps with S hooks? How do you know they are illegal?

TeamSand, That's "S" traps, as in plumbing, not S straps as in bungee jumping.
Back to the question.
Fred,
Chapter Seven, Section 703.5(b) titled "Prohibited Traps" of the Standard Plumbing Code Book states; Full "S" traps are prohibited.
Back 40/50 years ago "S" traps were used because it didn't use a vent and cut down on construction costs. However by not venting a fixture the suction caused be draining a fixture would suck enough water out of the trap seal to allow sewer gas to escape. This is when building departments began to listen to complaints from home owners and outlawed "S" traps. "S" traps are outlawed in all the U S states and Canada. And now you know the rest of the story. Regards, Tom