One fixture versus many fixtures
One slow sink or tub can be local. Multiple fixtures backing up, a toilet bubbling when another fixture drains, sewage in a shower, or floor drain overflow may point beyond one trap.
Stop using water
If sewage or dirty water is backing up, stop adding water. Pause laundry, dishwasher, showers, sink use, and flushing.
Olympia system clues
Some Olympia-area homes connect to public sewer. Others involve side sewer questions, septic, grinder, or STEP equipment. If an alarm is sounding, a cleanout is overflowing, or you know the system type, include it.
What not to do
Do not mix drain chemicals. Do not keep flushing to test the line. Do not remove a cleanout cap if wastewater may be pressurized. Do not enter contaminated water to investigate.
Useful details when you call
Say which fixture backed up first, which other fixtures gurgle or rise, whether sewage is visible, and whether rain, laundry, or heavy use came right before the backup.