Normally a shower and toilet do not clog at the same time, so when yours does you must proceed with caution. While you first should attempt to clear the clogs using traditional methods, you may be dealing with a major clog that calls for more advanced unclogging methods.
Plungers apply pressure to a drain line by sealing off the drain opening. When you pump the plunger's handle hard up and down, while still keeping the plunger's cup sealed over the drain opening, you dislodge clogs that sit toward the top of the drain pipe. When plunging a toilet, use a funnel-cup plunger. Funnel-cup plungers have a rounded bottom to the rubber cup, allowing the cup to sit in the toilet's drain opening more effectively.
Snake the Drains
When a plunger does not unclog the drains, turn to a drain snake or auger for further help. A drain snake has a long flexible line that literally feeds down the drain pipe, coming into direct contact with any blockages along the way. Spinning a crank on the snake's housing will spin the flexible line. When you feed the auger into the drain, spin the crank clockwise. As you pull the snake out of the drain, spin the crack counterclockwise. You may need to snake a toilet's drain pipe up to three times to eliminate clogs completely.
Check Vent Pipe
When the shower and toilet clog at the same time, it is possible that a single cause created both clogged drains. All drain pipes in the bathroom feed into a larger drain pipe, which also connects to a vent pipe. The vent pipe opening sits above the house's roof line. This pipe expels the sewer gasses in the drain pipes as well as replaces air that washes down the drain pipes along with the waste water. By climbing onto the roof and shining a flashlight down the pipes, you will see if a clog exists. Shooting water down the vent pipe will clear some clogs and restore the drain system to normal functioning.
Call in a Plumber
When you have attempted to unclog the toilet and shower, as well as the vent pipe over the bathroom and still do not have any success, you must call a local plumber for help. The cause of both drains backing up likely sits in the main drain pipe that connects your house's plumbing to the sewer. A plumber has the expertise and necessary tools to clear major clogs in the sewage drain line, since such a clog will create even more problems with your house's plumbing in the near future.