Pumping Schedule

We are often asked how often a septic tank should be pumped, this schedule is a good rule of thumb.

If you have a garbage disposal you should pump your tank more frequently. 

We do not pump tanks but can recommend who you should call.

Table I. Septic Tank Pumping Frequency in Years
. Household size – Number of Occupants
. 1 2 3 4 5 6 7 8 9 10
Tank-Gallons Septic Tank Pumping Frequency in Years
500* 5.8 2.6 1.5 1.0 0.7 0.4 0.3 0.2 0.1
750* 9.1 4.2 2.6 1.8 1.3 1.0 0.7 0.6 0.4 0.3
900 11.0 5.2 3.3 2.3 1.7 1.3 1.0 0.8 0.7 0.5
1000 12.4 5.9 3.7 2.6 2.0 1.5 1.2 1.0 0.8 0.7
1250 15.6 7.5 4.8 3.4 2.6 2.0 1.7 1.4 1.2 1.0
1500 18.9 9.1 5.9 4.2 3.3 2.6 2.1 1.8 1.5 1.3
1750 22.1 10.7 6.9 5.0 3.9 3.1 2.6 2.2 1.9 1.6
2000 25.4 12.4 8.0 5.9 4.5 3.7 3.1 2.6 2.2 2.0
2250 28.6 14.0 9.1 6.7 5.2 4.2 3.5 3.0 2.6 2.3
2500 30.9 15.6 10.2 7.5 5.9 4.8 4.0 3.5 3.0 2.6

ARE ADDITIVES USEFUL? – Septic System Additives and Chemicals – are they needed?

Septic Additive Companies are Asked for Independent Supporting Research

Many septic treatment producers and distributors contact us with suggested products. We ask for independent, peer-reviewed, professional research supporting each suggested product. Such support is particularly needed for two reasons:

The high cost of replacing a failed septic absorption field or seepage pit system naturally breeds an industry of “magic bullets” which are questionable (see the citations which follow.)
Because of the lack of demonstrated effectiveness, and perhaps more important, because some septic additives or cleaners are dangerous or can cause serious ground water contamination they are illegal in many jurisdictions.
Septic tank additives or “rejuvenators” are not needed in your septic tank, whether the additives are chemically-based (organic or inorganic compounds that claim to break up sludge or scum or to unclog drainfields), or biologically-based septic additives (septic tank yeast cultures, septic tank bacteria, starter bacteria, or septic tank enzymes).

Some septic tank or septic drainfield additives such as yeast or harsh chemicals can actually damage the septic system. Yeast can cause frothing and excessive activity in the septic tank, preventing normal settling of solids and coagulation of greases. This agitation forces solid waste into the drainfield and by clogging the soil, shortens its life. Other septic chemicals intended to kill tree roots or unclog clogged leachfield soils can contaminate the environment.

Can Some Conditions Kill Off Needed Septic Tank Bacteria?

If other conditions at a property have resulted in killing-off the (needed) septic tank bacteria (such as adding unusually large amounts of bleach, disinfectants, or antibiotics to a septic tank) some folks sell bacterial “starters” to “rejuvenate” the septic tank. To me this makes little sense for the following reasons:

Calculations of “septic tank die-off” which demonstrate that about 2 gallons of bleach is likely to harm septic tank bacteria have been based on a “static septic system”, a fixed septic tank volume into which no new wastewater, sewage, and their diluting and re inoculating effect have been considered.

If you don’t correct the conditions that have caused a bacterial die-off in the septic tank, no amount of starter or booster is going to make any difference.

Adding products such as enzymes which claim to break down grease risk destroying the floating scum layer in the septic tank, forcing unwanted oils and debris into the leach field.

As soon as you stop putting inappropriate bleach, disinfectant, or antibiotics into the septic system and after the first time someone uses a toilet, the septic tank has been re inoculated with what it needs.

Forcing hydrogen peroxide or other chemicals into drainfield or leach field soils can damage the soil and contaminate the environment.

Things that should not be flushed down a toilet: 


  • Clothes dryer sheets used as fabric softener or to make your dry clothes “smell nicer” – the quantity of chemical in these sheets is unlikely to be sufficient to damage the septic tank bacteria, but the synthetic fabric from which dryer sheets are made will not break down in the septic tank. These items not only add to the solid waste in the septic tank, a dryer sheet might clog the septic tank inlet at the baffle. 
  • Cat Litter: clogs pipes, septic baffles 
  • Chemicals: photo chemicals (see page top photo), paints, thinners, oils, varnishes, pesticides, used motor oil, unwanted cooking oil should never be flushed down a toilet nor put into any other building drains.
  • Cigarette butts are not biodegradable and should not be flushed into the septic system.
  • Coffee grounds should not be flushed into the septic system.

  • Diapers, cloth, disposable, cotton, paper, plastic should never be flushed down a toilet. Things like a baby diaper, that is, little nappies and other things that do not dissolve in water or are generally not biodegradable, things that are big enough to risk clogging a drain line, if flushed down a toilet, at the least, increase the pumping frequency needed at the tank, and at the worst, may damage the system leading to costly repairs.



  • Dirt – such as from people who clean their flower pots in the bath tub should never be flushed down a building drain
  • Drugs, prescription or prescription medicines, should never be flushed down a toilet unless your pharmacist or the drug manufacturer tells you specifically that the particular drug is absolutely harmless to the environment. 
    • Latex condoms, gloves, or similar products – we discuss condoms in septic systems further in the next section of this article.
    • Paper towels and facial tissues (Kleenex(TM)) do not break down easily and should not be flushed into the septic system. Toilet paper breaks down quickly and should not be a problem in an ordinary septic tank system.
    • Panty liners should never be flushed down a building drain
    • Plastic bags or other plastic scrap or trash of any kind should never be flushed down a building drain
    • Sanitary napkins should never be flushed down a building drain
    • Swimming pool chemicals and swimming pool back-wash water should never be flushed into a septic tank. It may seem surprising but we’ve been asked if it was ok to discharge swimming pool into a septic tank
      • High volumes of water from a pool into a septic tank will flood the tank and prevent proper processing of the waste therein
      • High volumes of water from a pool backwash onto a drainfield will flood the field and prevent proper processing of the septic tank effluent that is meant to be discharged there.
      • You should not discharge swimming pool backwash into a septic tank, ever
      • You should not discharge swimming pool backwash anywhere within 100 feet of a drainfield..
      • See details about the effects of swimming pool backwash water volume, flow rate, and chlorine at CHLORINE IN SEPTIC WASTEWATER
    • Tampons should not be flushed down a building drain
    • Trash and scrap such as dental floss should not be flushed down a building drain
    • Toys should never be flushed down a building drain – this may seem odd, but little kids may toss a toy car, doll, or other object into the john where it’s at risk of causing a costly clog. At an apartment in Wappingers Falls, NY, the guest toilet frequently clogged and overflowed. We finally removed the toilet to find a huge toy bone wedged across the drain. Prior owners’ dog perhaps had been washing off his treat. Had the bone moved end-ways into the drain this could have been a more costly repair.



    Underpants – or other cloth items. leads to a troublesome drain clog and toilet overflow problem. Cloth does not degrade in a septic tank.       

    Actually it’s quite common for small children to flush toys, diapers, underpants, or just about anything down the toilet. Something to be avoided. 

    Child Safety Warning about Toilets: an open toilet can be a child drowning hazard. Toilet lid locks are available for use in households with toddlers.

      Water in large quantities from roof gutters or surface runoff should be directed well away from the septic tank and drainfield areas and should never be discharged into the septic system. A septic system for handling onsite wastewater is designed to handle normal household wastewater flows from showers, sinks, tubs, laundry, etc., not roof runoff or surface drainage. Do not let roof gutters or surface runoff drain into an area where that water can enter the septic tank or drainfield.