What Not to Flush or Pour Down a Septic System
A septic system handles household wastewater slowly, using bacteria to break down solids while liquids drain into the soil. It is not a garbage disposal for the whole house.
Items that do not break down, kill bacteria or add too much water can clog pipes, fill the tank faster and damage the drain field.
Knowing what to keep out of the system is one of the simplest ways to avoid messy, costly problems. If you are unsure about a specific product or your system’s limits, ask a qualified local septic professional or your local health department.
Wipes and paper products
So called flushable wipes are a common cause of clogs. Many do not break down the way toilet paper does, even when the label suggests they are flushable.
- Baby wipes, cleaning wipes and makeup wipes
- Paper towels, tissues and napkins
- Cotton balls, cotton swabs and dental floss
- Feminine hygiene products and diapers
Toilet paper is designed to break down. Everything else belongs in a trash can.
Fats, oils and grease
Grease cools and hardens as it moves through the pipes. Over time it can build up and narrow the line, and it can also add to the solids in the tank.
- Cooking oil, bacon grease and pan drippings
- Butter, margarine and heavy sauces
- Dairy products in large amounts
Pour cooled grease into a container and throw it away. Wipe pans with a paper towel before washing.
Chemicals and harsh cleaners
A septic system depends on bacteria to work. Strong chemicals can reduce that bacterial activity, and some can harm the soil in the drain field.
- Paint, solvents, thinners and varnish
- Pesticides, herbicides and fertilizers
- Large amounts of bleach, drain cleaner or antibacterial products
- Motor oil, antifreeze and other automotive fluids
Small amounts of normal household cleaners are usually fine. Avoid dumping leftover chemicals down the drain, and check with your local health department about proper disposal options.
Medications and other household items
Flushing unused medicines can send them into the tank and eventually into the soil. Many communities have take back programs for unused medication.
- Pills, liquids and patches
- Cat litter, including clumping types
- Coffee grounds, eggshells and fibrous food scraps
These items either do not break down well or add unnecessary solids. Trash or compost them instead.
Too much water at once
Water volume matters as much as what is in it. A system can only process so much at one time, and a heavy flow can stir up solids and push them toward the drain field.
- Long showers back to back
- Doing several loads of laundry in one day
- Running the dishwasher and laundry at the same time
- Hot tubs or large tubs drained into the system
Spread out laundry over the week when you can, and fix running toilets and leaky faucets promptly. If you are not sure how much your system can handle, ask a qualified local septic professional.
How often pumping may be needed
Even with good habits, solids build up in the tank. Pumping is often needed every few years, but the right interval depends on household size, tank size, water use and local conditions. Some systems may need service sooner, and some may go longer.
The general guidance is to have the tank checked periodically and pumped when the sludge and scum layers get too thick. Your local rules may set specific requirements.
To find help in your area, you can start at the Septic Tank Pumping Directory homepage, or look for septic tank pumping contractors in Maryland if you are in that state.
Homeowners elsewhere, such as those searching for septic tank pumping contractors in Tennessee, can use the same directory to find local listings.
Next steps
- Post a short list of do not flush items near the toilet for guests
- Put a small trash can with a lid in every bathroom
- Scrape plates into the trash before washing
- Spread laundry loads across the week
- Schedule a tank inspection and ask about pumping timing
- Contact your local health department with questions about disposal or local requirements
Good habits reduce the chance of clogs and early drain field problems. When in doubt about a product or your system, ask a qualified local septic professional rather than guessing.