How Does a Toilet Affect Septic Tank Function?

Posted by Tank Techs on December 31, 2019


The loss of this $1.25 M. toilet made big news. They discovered it was missing when the palace flooded. You definitely do not want your toilet making news, so it is best to understand how its use can affect the septic tank. Things to take into consideration:

How many people are in the house?

Does it surprise you that septic tank size is based on the number of bedrooms, not bathrooms, in the house? Local regulations vary, but commonly a 5-bedroom house will have a 1500 gallon tank and a 3 bedroom house will have a 1000 gallon tank. If the occupancy of the house is above average, the number of flushes per day is going to be more than anticipated. Sometimes, bedrooms will be added later and the smaller tank is not taken into consideration. This can keep the septic tank from working properly

Male or female occupants?

Females tend to put a higher demand on septic tank.

Age of occupants?

The very young and the very old tend to put a higher demand on a septic tank.

How many gallons of water are used to flush?

Toilets manufactured before 1982 generally use 5 to 7 gallons per flush. A change in federal law since then lowered that to NO MORE than 1.6 gallons per flush. Because the average person flushes the toilet 5 times a day, replacing your old toilet with a newer, more efficient one can reduce the water going into the septic tank from 140 gallons per day to 32 gallons a day in a four person household.

How about leakage?

The US Geological survey has found that many toilets have a constant leak that causes them to waste somewhere around 22 gallons of water per day. This translates into about 8,000 gallons per year. Adding this extra water to the water that is actually used can cause a quick turnover of water in a septic tank, preventing the tank from doing its job and possibly even pushing solids out to the rest of the system. It has also been noted that if there is one leaking toilet in the house, there is likely a second one also.

What is being flushed?

Whatever goes down the toilet is going into a big box in the ground (that is really what a septic tank is), so if it doesn’t have the ability to quickly breakdown, it will have to be pumped out. Think about that before flushing anything. The Flushing Rule is simple: NOTHING but waste and toilet paper* should ever be flushed. Nothing. Even wet wipes that are marked flushable can cause problems when they do not disintegrate like you think they do. It would be great if we didn’t have to make this list, but because these are things commonly pumped out of septic tanks, please don’t even consider flushing cigarette butts, feminine hygiene products, unused medications or the leftover grease or food from cooking.

*Contrary to what you may hear, toilet paper can easily be handled by a septic tank under normal usage. Some toilet papers break down faster than others, so it isn’t a bad idea to keep that in mind.

Keeping your toilet out of the news…

Here are a few toilet/flushing related tips that may help you keep your septic tank functioning properly.

  • Know your usage – be aware of any factors that may challenge your tank and address them
  • Replace old toilets
  • Check regularly for leaks
  • If you did not eat it or drink it (and it isn’t toilet paper), DO NOT flush it
  • Use TankTechsRx for Septic Systems
    • 1 liter a year for average tank usage
    • If your tank is under high demand (more females, children, or elderly occupants), consider more frequent treatment (8 oz monthly or bimonthly) to account for higher water turnover in the tank

Have questions or concerns about your toilet or septic system? Get in touch. We can help!

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