Pumping (Cleaning Out a Septic Tank)

Cross-section of a two-compartment septic tank being pumped Most home septic tanks require cleaning every three to five years.

Pumping is needed when solids fill from one-third to one-half of the tank. The only way to know when this occurs is to have your tank inspected by a septic contractor. The contractor will recommend pumping by a licensed septic pumper whenever:

  • The bottom of the scum (grease) layer is within 6 inches of the bottom of the outlet tee.
  • The top of the sludge layer is within 12 inches of the outlet tee.

After the tank is pumped, there is no need to "reseed" it. Seeding means to jumpstart good bacterial growth by adding things such as yeast, manure, or dead animals. DHEC doesn't recommend seeding the system because the simple act of using the system will provide all the bacteria necessary to make the system work well.

Yeast, manure, meat, and dead animals will not help develop the colony of bacteria in the tank any faster.

General Advice on Septic Tank Pumping Frequency

  • For a 1,000-gallon tank
    • Number of residents: 1 — Pump every: 12 years
    • Number of residents: 2 — Pump every: 6 years
    • Number of residents: 4 — Pump every: 3 years
    • Number of residents: 6 — Pump every: 2 years
    • Number of residents: 8 — Pump every: 1 year
  • For a 1,250-gallon tank
    • Number of residents: 1 — Pump every: 16 years
    • Number of residents: 2 — Pump every: 8 years
    • Number of residents: 4 — Pump every: 3 years
    • Number of residents: 6 — Pump every: 2 years
    • Number of residents: 8 — Pump every: 1 year
  • For a 1,500-gallon tank
    • Number of residents: 1 — Pump every: 19 years
    • Number of residents: 2 — Pump every: 9 years
    • Number of residents: 4 — Pump every: 4 years
    • Number of residents: 6 — Pump every: 3 years
    • Number of residents: 8 — Pump every: 2 years

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Septic Septic Tank Alerts