Septic System Backing Up
A septic backup - sewage returning into your sinks, toilets, or showers - is a plumbing emergency that may involve a full tank, blocked outlet baffle, clogged effluent filter, or failing drain field. Stop all water use immediately and describe the situation to General Septic. Do not flush toilets or use any drains until the condition has been evaluated.
What to do right now
Stop all water use right now - every flush and sink run makes the situation worse. Use the request form to describe the emergency to General Septic. Most pump chambers have little to no reserve when sewage is already surfacing inside the home.
Common Causes
1Full or Overloaded Tank
The most common cause. A tank that has not been pumped in 3–7+ years accumulates sludge until there is no room for incoming wastewater. Sewage has nowhere to go but back into the house.
2Blocked Outlet Baffle or Effluent Filter
The outlet baffle or effluent filter keeps solids inside the tank and out of the drain field. When these become clogged - by grease, hair, or excessive solids - drainage from the tank stops entirely, even if the tank is not full.
3Saturated or Failing Drain Field
If the drain field soil is saturated, it cannot accept more effluent. Liquid backs up through the tank and into the home's plumbing. This is a more serious condition than a full tank and may require drain field repair or replacement.
4Broken or Collapsed Pipe
A crushed, cracked, or root-intruded pipe between the house and the tank can block flow entirely, causing immediate backup regardless of the tank's level.
5Frozen Pipes or Tank Inlet (Winter)
In freezing temperatures, the inlet pipe or the area just inside the tank lid can freeze, blocking drainage. This is more common after a very cold snap following low water use.
What to Do
- 1
Stop all water use in the home
Turn off washing machines mid-cycle. Do not run dishwashers, use faucets, or flush toilets. Every gallon added to the system worsens the backup and makes cleanup harder.
- 2
Keep people and pets away from backed-up areas
Raw sewage contains pathogens - bacteria, viruses, and parasites. Restrict access to affected bathrooms and any outdoor areas where sewage may have surfaced.
- 3
Describe the emergency request
Use the request form to describe which fixtures are backing up, whether it is all drains or just one, and when you last had the tank pumped. General Septic can confirm the equipment and scope needed.
- 4
Document affected fixtures and timing
Note whether the problem started suddenly or gradually worsened, which fixtures are affected, and any recent changes in usage (guests, extra laundry). This gives General Septic useful context.
What to Avoid
- Do not use chemical drain cleaners - they kill the bacteria your tank needs and do nothing for a full tank or saturated field
- Do not flush toilets - every flush adds to an already overwhelmed system
- Do not run any water-using appliances (dishwasher, washing machine, any faucet)
- Do not attempt to open or access the septic tank yourself - gases inside can be lethal
- Do not ignore backup and hope it clears - it will not, and continued use accelerates drain field damage
Related Services
Emergency Service
Emergency septic service for backups, alarms, and overflows.
Septic Pumping
Routine septic tank pumping and cleaning to help manage accumulated solids.
Drain Field Repair
Restoration and rejuvenation for failing or saturated drain fields.
Septic Repair
Repairs for broken baffles, crushed pipes, and failing pumps.
Request Guidance in the Greater Seattle Area
General Septic helps property owners across King, Pierce, and Snohomish counties request direct septic service from General Septic. Use the form above to share the relevant details.