Why Do Septic Systems Fail?

Five common causes of back-ups

Anyone with a septic system dreads septic failure. Wastewater backs up into the house through drains and toilets. It makes a big mess that requires costly cleanup.

Fortunately, most causes of septic failure can be avoided if you know what they are.

Here are the most common sources of septic system failure:

Improper design and installation

The first step to avoiding backups is good septic system design. It might seem simple, but there are a few factors that you have to take into account.

One of the most important things for septic system success is soil composition. Some soils provide excellent wastewater treatment while others don’t. For this reason, septic system drainfield design is based on soil analysis.

If designers overestimate the amount of wastewater soil can take, they may make the drainfield too small. They might also fail to take higher seasonal groundwater tables into account. Both things cause system failure.

The right size septic tank is also essential. If it’s too small, solids clog the drainfield, which can also result in system failure.

Without a watertight septic tank, water can leak into or out of the system. If untreated water is leaking out, it poses a health risk.

Water leaking into the tank can also cause problems. If water from the environment gets into the tank, it can lead to hydraulic overloading. Hydraulic overloading just means there’s more water in the tank than it can process. It can cause wastewater to back up into the house, or leak into the yard untreated.

Once the system design is right, the septic system installation has to be right, too. The drainfield has to be properly leveled. Surface drainage needs to be diverted away from the field. Otherwise, wastewater and rainwater can saturate the field and overload the system.

During and after installation, take care not to park cars or other heavy machinery on the drainfield. It leads to soil compaction, which interferes with wastewater flow.

Toxic chemicals and cleaners

Your septic system contains living microorganisms and bacteria that digest waste. Flushing toxic household cleaners, disinfectants, and bleach can disrupt these natural processes. Too much chlorine water in your system can also upset its natural biology.

Read the labels on cleaning products to see how toxic they are to your system. In general, septic system bacteria recovers quickly after small doses of cleaning products. Some cleaners are less toxic to your system, but others should only be used in small amounts.

As long as you follow the guidelines on product labels, you can keep your septic system safe.

Flushing the wrong things

Your system’s microorganisms and bacteria are great at digesting organic material, but there are things they can’t digest. If you flush things that don’t easily break down, they build up in the tank and cause blockages.

To avoid problems, never flush

  • Rubber gloves
  • Latex products
  • Cotton products
  • Dental floss
  • Cigarette butts
  • Plastics
  • Metals
  • Sand
  • Cat litter
  • Soil
  • Other inorganic material

Only flush toilet tissue and human waste.

Excessive water use

Excessive Laundry can cause issuesIf your hot tub or spa drains into the septic system, the hot water will stir the solids in the tank and push them out into the drainfield. The system will clog and fail.

Doing all the household laundry in one day can also flood the system. Washing load after load doesn’t allow time for your septic system to adequately treat waste. It floods your drainfield without allowing enough recovery time.


Your best bet is to spread out your water use. Go ahead and leave some laundry for tomorrow, and make sure your hot tub doesn’t drain into the septic system.

Water purification systems

Some water purifiers pump excess waste into the septic system. Hundreds of gallons of water can flow into the septic tank, which might be more than it can handle. This flooding agitates the solids and causes excess flow to the drainfield.

Avoid this by rerouting drainage from water purification systems like water softeners.

If you’re already experiencing septic system failure, the easiest solution is Septic Rescue. If it doesn’t work for you, we offer a 100% money-back guarantee.

Fix your failing septic system now