Why Does Size Matter?
A septic tank breaks down solids with bacteria, storing the remainder and dissipating the liquids. If the tank is too small, it will fill before the process is complete, preventing the breakdown of waste and leading to buildup. If it is too large, there won’t be enough in the tank to efficiently allow the bacteria to break down the waste, leading to further problems.
What Size Should I Buy?
Tank size should be directly related to the number of people creating waste and using water in the home. But it is important to consider the future as well and be sure to plan for future occupants of the home. For example, a four bedroom home with two occupants shouldn’t get a smaller tank, rather a tank should be chosen for the expected number of occupants in a four-bedroom home. While individual needs differ, here is a general guide:
- One or two bedrooms: 750-gallon tank
- Three bedrooms: 1,000-gallon tank
- Four bedrooms: 1,250-gallon tank
In general, the size should increase by several hundred gallons for each additional expected occupant.
Don’t Forget About Water Usage!
While the number of people living in the home and the overall size are important factors, what ultimately matters is water usage. This varies significantly on a per-person basis, and before purchasing, it is helpful to research your own water consumption. In general, your new septic tank should be between 1.5 and 2 times the size of your total daily household water consumption.