5 Top Myths About Septic Systems

There's a lot of misinformation out there about septic systems. Here's what you need to know.

residential septic system PlazacCameraman/Getty Images

If you’ve got a septic system at your house, then you’ve probably picked up advice about managing that system that simply isn’t true. Here are the five top septic system myths dispelled.

Septic Myth #1: Pump-Outs Are Unnecessary.

The truth is, having a septic tank pumped every two or three years is the best and most economical way to keep your system working.

The no-pump myth comes from companies selling septic additives. The claim is that by adding secret microbes and enzymes to the system it can foster complete sewage digestion, eliminating the need to have the tank pumped every few years. It’s an attractive idea, but risky and based mostly on hope. How do you know indigestible sludge isn’t building up to dangerous levels in your tank as you opt for no pump-outs, year after year?

And besides, is there really an additive that can cause the complete digestion of hair, lint, fingernail clippings, fat and all the other indigestibles that build up on the floor of a septic tank? Pump-outs are the only way to ensure that damaging levels of indigestible solids are not rising to the level of the tank outlet and flowing out to clog your system’s leaching pipes.

Septic Myth #2: It Doesn’t Matter What You Put Down the Drain.

It actually matters a great deal what you put into a septic system.

While it’s true that septics can be quite reliable and easygoing, putting poisons such as drain cleaner, disinfectants and solvents down your drain will diminish or eliminate the microbes that digest sewage, increasing the risk of system failure. Even just one cup of household bleach, for example, can kill all beneficial microbes in a 1,000-gal. septic tank for a time. These microbes will eventually re-establish themselves, but not until some sewage goes undigested.

Another big no-no? Coffee grounds. They don’t readily digest and can get into your leaching bed, where they can contribute to system failure.

There are just two things that can safely be put into a septic system: waste water and sewage.

Septic Myth #3: Flushing a Dead Mouse Down the Toilet Helps a Septic System.

Some say that a dead mouse contains unique microbes that improve septic system performance. This is false. Every time you flush a toilet for the usual reasons, you’re introducing a fresh infusion of beneficial microbes. While the old mouse trick seems wise and reassuring, a few ounces of dead animal isn’t providing anything essential that’s not already coming from other sources.

Go ahead and flush dead mice down the toilet if you want, but you’re not doing your septic system any favors. In fact, septic additives in general (even “natural” ones) are questionable, at best. (See Myth #1.)

Septic Myth #4: You Can’t Expect a Septic System to Last More Than 20 Years.

Truth be told, many septic systems keep working perfectly after two decades of service. I know because I’ve met many people with 20-plus-year-old systems. The oldest I’ve seen so far is 49 years old, and still working perfectly.

At the other end of the spectrum, I’ve seen septic systems fail after just five years of use. Septic system working life has much more to do with management than it does with some arbitrary lifespan expectation. Have the tank pumped every two or three years, avoid putting poisons down the drain and keep your leaching bed mowed and free of anything other than grass to up your system’s changes of a long working life.

Septic Myth #5: Clogged Septic Systems Must Be Replaced.

The fact is, many clogged septic systems can be restored with maintenance, so replacement isn’t always necessary.

Three of the most common causes of clogs—indigestible sewage solids entering the leaching bed, slimy biomat growths blocking the holes in the perforated leaching pipes and tree roots physically clogging the leaching pipes—can usually be solved without replacing any part of the system.

Instead, look into a process called “jetting,” which involves installing access ports on the ends of the leaching pipes so you can give them an internal pressure-wash to clear them out. There’s no reason that a septic system can’t function indefinitely if the leaching pipes and bed are jetted internally with high-pressure water from time to time.

Other than having the septic tank pumped every few years, jetting is the simplest and most effective option for restoring a failed or failing system. I’ve seen a septic system clogged so badly that there was 12 in. of raw sewage sitting above the top of the tank; yet this same system functioned perfectly for years after jetting the leaching pipes.

And speaking of septic systems, here are the 20 dirtiest jobs in the world.

Steve Maxwell
Steve Maxwell is an award-winning content creator who has published more than 5,000 articles, shot countless photos and produced video since 1988. Using his experience as a carpenter, builder, stone mason and cabinetmaker, he has created content for Mother Earth News, Reader's Digest, Family Handyman, Cottage Life, Canadian Contractor, Canadian Home Workshop, and many more. Steve lives on Manitoulin Island, Canada with his wife and children in a stone house he built himself. His website gets 180,000+ views each month, his YouTube channel has 58,000+ subscribers and his weekly newsletter is received by 31,000 subscribers each Saturday morning.