A septic tank and absorption field are built to handle ordinary household wastewater. Many solids, chemicals, and products that go down modern drains make that job harder.
What should stay out of the drains is a different question from how to protect the yard system from vehicles, structures, and surface water.
What enters the house sewer drain reaches the septic tank and, eventually, the absorption field.
Materials that do not belong in the system can increase solids, clog pipes or the field, interfere with treatment, or overload the tank and the absorption area.
Examples below are drawn from New York State Department of Health septic system guidance. They are categories and illustrative items—not an exhaustive inventory of every household product.
Items that do not break down easily—such as paper towels, cotton swabs, personal hygiene products, condoms, disposable diapers, coffee grounds, cat litter, facial tissues, dental floss, cigarette butts, plastics, grease, or bones—do not belong in the system.
Avoid flushing or using strong chemicals and bacteria-disrupting products such as drain cleaners, solvents, paint, paint thinners, floor/sink cleaners, motor oil, antifreeze, pesticides, and photo chemicals. These may disrupt septic tank or absorption-system operation.
Cooking fats and oils contribute to scum and loading. Keep them out of drains whenever possible.
Many disposable hygiene and cleaning-related solids are designed not to degrade quickly. If it will not break down readily, it should not go into the septic system.
NYSDOH lists medications among materials that should not be flushed. Do not use the septic system as a disposal route for unused medicines.
The same guidance groups other non-degradable or disruptive materials—plastics, grease, bones, and similar solids—with the “don’t flush” list. When unsure, keep it out of the drain.
NYSDOH notes that household bleach, disinfectants, cleansers, and antibacterial soaps, when used in normal household applications, should not affect system operations.
The distinction is between ordinary use and dumping strong solvents, concentrated chemicals, or industrial-style products into the system.
New York State Department of Health guidance advises avoiding septic-tank additives.
A septic tank that is properly sized and maintained can adequately manage household wastewater without additives.
Additives are not a substitute for knowing what failed, protecting the absorption area, or evaluating repair versus replacement when major problems appear.
Garbage disposals or grinders can substantially increase solids accumulation in the septic tank and absorption field.
NYSDOH notes that if they are used, tank size may need to be increased and pump-outs may be needed more often. Reducing food-waste solids at the sink remains the more protective habit for many systems.
For physical protection of the yard system—vehicles, structures, landscaping, and drainage—see how to protect your septic system.
Don’t-flush and additive guidance paraphrases New York State Department of Health septic system operation and maintenance materials.
New York State Department of Health
Publication: Septic System Operation and Maintenance
Schoharie Septic Systems is not affiliated with the New York State Department of Health. Information attributed to NYSDOH on this page is paraphrased from the agency’s publicly available septic-system materials and should be checked against the current official publication.
Open the official NYSDOH publication
NYSDOH Find Out More contacts listed on the publication: health.ny.gov/DrinkingWater · Local health department contacts · (518) 402-7650
NYSDOH advises avoiding septic-tank additives and states that a properly sized and maintained tank can manage household wastewater without them.
NYSDOH indicates that household bleach, disinfectants, cleansers, and antibacterial soaps used in normal household applications should not affect system operations. Strong solvents and concentrated chemical dumps are a different category and should be avoided.
NYSDOH includes medications among materials that should not be flushed into a septic system. Use approved medication take-back or disposal guidance instead of the drain.
Changing drain habits can help protect a working system. If backups, odors, slow drains, or wet ground are already occurring, the cause should be investigated rather than treated with additives.
