The septic tank will resume normal water level soon after being pumped. The purpose for having your tank pumped is to remove sludge that will, if not routinely removed, ultimately lead to system failure. As soon as you flush a toilet, take a shower or do laundry, you are again sending water into the septic tank. It is normal to see water in the tank. However, the water level must be at or below the bottom of your outlet line. If the water level is above the outlet line, there is a problem with the system. If this is the case, call your service provider for assistance.