Man, a buddy of mine hit the same thing last month, lady's kids had stuffed a whole pair of toddler socks in there. He yanked the filter, cleared it out, and it drained fine, she almost paid some other guy for a whole new pump.

That $18k drop is huge, congrats on sticking with it. I know that feeling of dread when a government site looks like a relic from the dial-up days, it took me three separate tries to even find the right form for my property in King County. Finding those buried examples with real numbers makes all the difference, it's like they hide the useful stuff on purpose.

Honestly never gave OPs a second thought until one spoiled a death for me.