Can medications harm my septic system?

If someone in your home is taking medications for an extended period, you may want to have your septic tank pumped more often.

Photo by Beth Clawson, MSU Extension.

The EPA estimates that 25 percent of the homes in the U.S. have a septic system, a decentralized, cluster, or another similar non-municipal onsite wastewater facility. It is estimated 1.6 million or 43 percent Michigan homes have a septic system or are connected to an onsite wastewater system. The CDC reports that 48.9 percent of all Americans have used at least one prescription drug in the last 30 days and 23 percent have used three or more, and 12 percent have used five or more.

Consistent maintenance and regular inspections are the best way maintain a healthy septic or other onsite wastewater system. It is especially important to remember not to flush anything down your toilet that is not body waste or toilet paper. Overuse of household chemicals can impede the biological action of your home wastewater treatment system. This includes antibacterial soaps, harsh cleaning chemicals, and chlorine bleach. Septic tanks and drain fields depend on both anaerobic and aerobic bacteria to break down the organic waste and clean the water as it is released it into the soil for filtration.

Some chemicals from medications, such as antibiotics, antibacterials, and chemotherapy treatments, that do not completely metabolize in your body and are expelled in your waste. These chemicals can disrupt the biological action in your tank and drain field causing it to fill with solids more quickly. More solids in your tank risk solids flowing into the drain field leading to septic or onsite wastewater system failure. 

Some steps to protect a costly failure and potential replacement are:

  • Flush only body waste and toilet paper down the toilet, period
  • Use minimal household chemicals for cleaning
  • Avoid or use minimal amounts of chlorine bleach in your washing machine
  • Have your tank pumped more frequently if someone in your household is taking chemotherapy or antibiotic medications for an extended period
  • When your tank is pumped, ask your pumper to refill it with fresh water to dilute any residual medications
  • Take excess and unwanted chemicals, cleaners, and medications to your local household hazardous waste or medication collection program

In the Pumper Magazine, Sara Heger, Ph.D., says “It is important to note that most general medications and typical over the counter medications will not harm our septic or wastewater system.” However, some chemotherapy drugs either do not break down easily, can affect any organism, or concentrate in the urine. Adding additional water or extra flushes can help dilute the drug in your septic system.

For more information about the Michigan Septic System Education, contact Beth Clawson, MSU Extension Educator. To learn more about this and other water quality programs, contact Michigan State University Extension  Natural Resources educators who are working across Michigan to provide natural resources and water quality educational programming and assistance. You can contact an educator through MSU Extension’s “Find an Expert” search tool using the keywords “Natural Resources” or “Water Quality.”

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