This is a really hard episode to review without spoilers so here goes:
This episode is a exposition dump by George onto Sean and Julian. This Season we've seen Sean and Julian finally open their eyes to what is actually going on and that they've either being purposefully ignorant or completely in denial about Leeane and what she can do. It's something we've been waiting 4+ Years for. That is what makes this episode so bad. What George is explaining will have viewers frustrated and disappointed as it potentially undoes so much good character development that has happened.
Meanwhile Dorothy does at least finally start to piece some things together HOWEVER, like this show does with it's main characters, she's not figuring it out for herself. It's being pointed out directly. This time a Co-Worker is clueing her in on a discovery. She's supposed to be a "Investigative Journalist" yet she's the furthest behind of the group on what's going on in her own home.
There's 3 Episodes left in the Show, not just the season, yet they prove how bad their Writing is by trying to speedrun all this exposition and explanation in a single episode after dragging it out. We're at a total runtime of almost 20 HOURS watching this show and this episode makes it clear they intentionally wasted our time without it even being necessary to do that to their audience in the first place.
The biggest insult is that they've made the audience so desperate for actual answers and strung us along so long that most viewers are going to be happy with this episode. Sewer Water is refreshing if you're dying of dehydration after all.