No grandfather clause for it? We had a similar law (25 years) for exemption, but repealed it with a grandfather clause. Basically, any car 1974 or older (prior to unleaded gasoline laws) was exempt. If you guys are 30 year... looks like you'll be coming up on the same timeline soon.
If they have the grandfather clause in it, you should be OK. If not, see if you can move to Southern Oregon;)
MiniD