While taking a shower after a few minutes the sink will make noises and then the toilet will gurgle and threaten to fill up with water. Usually at that point the shower drain will stop draining and water will build up in the shower. Once I turn the shower off everything drains (slowly) and the noises end.
No similar issues with the other bathroom. Both are on the same septic line.
Spock

Plumber, sounds like your vent stack may be clogged and maybe the drain too. If you want we can help you rod it if you are at all handy

Well, I would also say plumber. However, if you know of a company in your area that pumps septics and does drain cleaning, I would go with them. Really sounds like a partiall drain clog, but Ive seen full septics/ fualty drainfields do this to.

hile taking a shower after a few minutes the sink will make noises and then the toilet will gurgle It's a no brainer! Gurgles indicate a vent that's blocked. The sound you hear is the fixture venting itself by pulling air through the water in the trap. Like the other experts if you call in outside help it should be a plumber and not a septic tan k company. But hold on for a minute! Simply telling you to "call a plumber" isn't the Pumbing Page function. If it were we could answer all our questions with, "Call a Plumber".
This is a self help, do it yourself operation. The people that use us don't want to have to pay the high cost of "calling a plumber.
Let me show you how to solve your problem.
Your lavatory roof vent's clogged. You can rent a sewer machine at your local Home Depot or Rent All.
Locate the lavatory roof vent and feed the snake all the way to the base and 16 feet more. That's all there is to it. Good luck, Tom