Your septic tank is clogged. Not just full (that’s a different beast), but clogged. Solids have formed a dam, or the baffle is blocked.
Now go take a shower—but keep it short. Your bacteria are working. how to unclog a septic tank yourself
The Situation: You flush the toilet. Instead of a graceful swirl, the water rises like a horror movie villain. The shower drain gurgles a desperate goodbye. Worst of all? That smell near the backyard access port. Your septic tank is clogged