You are planning your dream home. The numbers of bedrooms are set. The floor plan is set. The decision to use an on-site septic system is set. Now the final question remains: What septic tank size do I need?

septic tank sizeSeptic Tank Size Matters

We have all heard the saying, but it is especially true when choosing a septic tank size for your home, business or property.

Too small of tank means there is not enough time for waste retention in the tank leading to less than ideal settlements of waste material.

What does this mean? The bacteria that are working to break down waste materials don’t have time to do their job before the waste is forced out to make room for more.

Too large a tank inhibits the creation of bacteria and the production of heat your system needs to run efficiently and optimally.

The bottom line of septic tank installation: size matters.

What Factors Matter?

There are plenty of factors that go into determining your water usage and needed septic tank size. Keep in mind that each state and county has their own minimum requirements, but a rule of thumb is your daily sewage flow should not be more than 60% of your tanks capacity. Keeping this in mind, other factors include:

Home Size and Occupants. Including the number of bedrooms and square footage of your home as well as the number of occupants. If it’s a two people in a small home, they need a smaller tank than a family of five in a large home.

Also keep in mind, this includes how many visitors you have and at what frequency. If your home is the local teenage hangout, that’s an important factor to consider.

Usage. While most estimates come from the size of the home and number of occupants, it’s also important to take a moment and evaluate your water usage.

What appliances are you using frequently? How many loads of laundry are done a day? How many showers? What type of water conserving habits does your household follow? When it comes to water usage, it’s important to get an accurate reading before installing your on-site septic system.

The Goldilocks Size

Industry standards use a basic outline to estimate tank sizes for households as follows. The Florida Department of Health, suggests the following tank sizes for residential homes based on daily capacity requirements…

  • 1 bedroom home, less than 750 sq. ft. – minimum of 900 Gallons Tank
  • 2 bedroom homes, less than 1,200 sq. ft. – minimum of 900 Gallons Tank
  • 3 bedroom homes, less than 2,250 sq. ft. – minimum of 1,050 Gallons Tank
  • 4 bedroom homes, less than 3,300 sq. ft. – minimum of 1,200 Gallons Tank
  • For each additional bedroom as 60 Gallons of Daily Capacity; For each additional occupant add 50 Gallons of Daily Capacity

It is important to note, these are general estimates. It is crucial to have a consultation with an on-site septic system professional before determining a tank size for your home or business.

So which septic tank size is just right for you home? You know, not too big, not too small, but just right?

Chris Bryan, Licensed Septic Contractor and Owner here at Advanced Septic Services of Clermont offers this explanation and solution:

“Septic Tank sizing is based on the anticipated gallons/day flow. This is calculated based on the living square feet of the house and the number of bedrooms. It gets a little tricky for larger homes and for older homes being replaced. I’m always happy to calculate for customers on a case by case basis and encourage them to contact me for their best options. ”

Lake County, Florida Septic Tank Sizing Rules

Lake County, Florida has their own set of minimum requirements for tank size and efficiency. It is important to factor these into your calculations, as a permit will not be issued if your tank is deemed to be below the minimum requirements.

Take a look at the general EPA chart below and for specific information on regulations and requirements read our article on septic system permits in Lake County or contact the Lake County Florida Department of Health.

Lake County Septic Tank Size Requirements

Septic Tanks Sizes Video


Proper sizing is important for septic systems, both for your personal home as well as your business. Tanks that are too small or too large disrupt the efficiency of your on-site septic system. For more information or to schedule a consultation you can contact us here or call 352.242.6100.