Essentially any large flush through my house (washer, shower) has started coming up through my basement drain in the floor. I bought this house two years ago for full price and already am 20k deep in hidden repairs (all from basement flooding, yayy). I can explain if I need to, but I really just don’t have extra funds to put to this after the others. I’m thinking I can’t bathe with more than a gallon of water and not wash dishes or clothing until I can fix it.
Edit: Thank you for all the comments. I’ll hire a plumber.
If it comes up the basement drain, then the obstruction is further down, and so you can’t really flush it from the drain and out. You need to find the sewer service well further out and flush it from there and in.
It’s likely a broken pipe taking in sand or branches, so flushing it won’t be a permanent fix. A plumber can probably fix it from outside too, so it doesn’t have to be very expensive.
You don’t need to waste your money on snakes and that kind of stuff. If a regular hose on full blast can’t loosen the obstruction from outside, then you need a plumber anyway.