Drains in our house have gotten progressively slower over the last couple of months

[Jonh Newman]

Drains in our house have gotten progressively slower over the last couple of months, and there's a gurgling sound from the downstairs toilet whenever the washing machine empties. No backups yet and no smell in the yard. My father-in-law insists it's just a plumbing clog and I should snake it, but something about the timing makes me think it's the septic side rather than the pipes. How do you tell the difference before you spend money on the wrong specialist? We're a household of five with teenagers, so water use is heavy and fairly constant. I'd like to know what to check myself before I start paying someone to tell me what I already suspect.

[hydrogenn]

Gurgling that shows up when a large volume drains is a classic septic side symptom, because the tank or the line to it is struggling to accept flow. A localized clog usually affects one fixture, not the whole house in sequence. So your instinct is better than his. Snaking won't hurt but probably won't fix it either. We were in the same spot and had Septic Solutions out for septic services; the tank was overdue and solids had carried into the outlet. Stop running back to back laundry loads until it's looked at, that's the fastest way to turn slow drains into a backup. Also note whether the gurgling happens only with big drains or with everything, that detail narrows it down considerably.