Signs your septic system is failing, and what not to flush

By the SepticRated team · Facts checked against the sources listed below on November 1, 2026. General information, not professional advice.

Warning signs

EPA lists these signs of a failing system:

• water and sewage from toilets, drains and sinks backing up into the home
• bathtubs, showers and sinks draining very slowly
• gurgling sounds in the plumbing
• standing water or damp spots near the septic tank or drainfield
• sewage odors around the septic tank or drainfield
• bright green, spongy grass over the tank or drainfield, even in dry weather
• algae blooms in nearby water
• a straight pipe discharging untreated wastewater to the ground surface
• high levels of nitrates or coliform bacteria in surface waters or drinking water wells

If you see any of these, call a septic professional.

What not to flush

EPA says only human waste and toilet paper should go down the toilet. Never flush:

• cooking grease or oil
• photographic solutions
• non-flushable wipes, such as baby wipes or other wet wipes
• feminine hygiene products
• condoms
• dental floss
• diapers
• cigarette butts
• coffee grounds
• cat litter
• paper towels
• pharmaceuticals
• household chemicals such as gasoline, oil, pesticides, antifreeze and paint or paint thinners

Water use matters too

Everything that goes down your drain ends up in your septic system. EPA says average indoor water use can be as much as 70 gallons per person per day, a single leaky or running toilet can waste as much as 200 gallons a day, and high-efficiency toilets use 1.6 gallons per flush or less.

How long the parts last

According to EPA, pumps and controls often need replacing every 10 to 20 years, concrete tanks may last 50 years or more, and a system more than 25 to 30 years old is likely near the end of its useful life.

Sources

• How to Care for Your Septic System, US EPA
• Frequent Questions on Septic Systems, US EPA