Short answer
For a working system, no. Penn State Extension says biological and chemical additives are not needed to aid or speed up decomposition, and the Ontario Onsite Wastewater Association notes independent studies found additives do not prevent sludge from building up. Regular pumping is what keeps the system healthy.
Types of additives
The Ontario Onsite Wastewater Association groups septic additives into three types:
- Inorganic compounds (acids, bases)
- Organic solvents (degreasers)
- Biological additives (bacteria and enzymes)
What the experts say
- Penn State Extension: biological and chemical additives are not needed to aid or accelerate decomposition.
- Ontario Onsite Wastewater Association: independent third-party studies indicate additives do not prevent sludge from accumulating, and claims that a product removes the need to pump should be treated with skepticism.
- A healthy septic tank and drain field normally contain enough bacteria on their own (Ontario Onsite Wastewater Association).
What works instead
- Pump on schedule: see how often to pump.
- Have the system inspected at least every 3 years (EPA).
- Flush only human waste and toilet paper (EPA). See septic safe toilet paper.
- Keep cooking grease and household chemicals out of drains (EPA).
- Spread laundry over the week so the tank isn't flooded (EPA).
Frequently asked questions
Can additives replace pumping?
No. Some solids in a tank, such as sand, grit and bits of plastic, can never be broken down by bacteria, so the tank still has to be pumped.
Are septic additives harmful?
Some can be. Strong acid or alkali drain openers can kill the tank's bacteria and corrode concrete tanks. Degreasers can also kill bacteria, and the solids they break up may flow out to the drain field and clog it.
Do I need to add bacteria after pumping?
A healthy tank gets the bacteria it needs from normal household waste. Penn State Extension says additives are not needed to aid decomposition.
Sources
- Septic Tank Pumping, Penn State Extension. Pennsylvania tank minimums by bedroom; additives not needed; pump when sludge reaches a third of tank depth.
- Septic Tank Additives, Ontario Onsite Wastewater Association. Types of additives and why they are not a substitute for pumping.
- How to Care for Your Septic System, US EPA. Inspect at least every 3 years; pump typically every 3–5 years; when to pump; garbage disposals; water use.
Prices are estimates for 2026, not quotes. Local codes, soil and access change the price, so get at least two written quotes and confirm the rules with your county health department.