How big should my septic tank be?

Managing your wastewater is an essential component of owning any home. Thanks to septic tanks, this can be easily dealt with. One of the most important things to consider however, is the actual size of the tank itself.

Today, that’s what we’re going to discuss – figuring out how big your septic tank needs to be. Let’s jump right in.

Why size matters

The size of your tank is hugely important for a wide range of reasons. For one, it’s going to be the first stop for all the wastewater that comes out of your house. This includes not just the toilets, but the showers, kitchen, laundry and the like.

Tanks generally hold the wastewater for a period of time before it separates the solids from the liquids. The bacteria in the tank will eventually break down the solids.

This is where the size is an issue. A tank’s efficiency is directly related to it’s own ability to break down waste If you choose a tank that’s too small, the pressure build up releases liquids too soon and the bacteria gets washed away along with solids that aren’t broken down properly.

On the other hand – if the tank is too big, then the tanks efficiency takes a big hit. Simply put, there won’t be enough liquids inside the tank for the bacteria to form and break down solids.

House size matters, too

The size of the house is often one of the best ways to manage how big your septic tank should be. We have the measurements broken down in the following way. Keep in mind, this isn’t perfect or necessarily even a recommendation. But it can serve as a good guidepost depending on the size of the home and the number of people living in it.

Under 1500 sq feet w/1-2 bedrooms – 750 gallon tank

Under 2500 sq feet w/ 3 bedrooms – 1,000 gallon tank

Under 3500 sq feet w/ four bedrooms – 1,250 gallon tank

Under 5,500 sq feet w/ five+ bedrooms – 1,315 gallon tank

Also water use

Not only is the side of the house important, but the amount of water you anticipate it using is also important. Your general water usage is also the most accurate way to judge what size your tank should be. Here’s how we broke that down:

500 gallons or less a day – 900 gallon tank

700 gallons or less – 1,200 gallon tank

900 gallons a day – 1,500 gallon tank

1,240 gallons a day – 1,900 gallon tank

Because tank size has a direct impact on the efficiency of your septic system, it’s important you put the proper amount of research into this decision. If you’re still stuck, give us a call and we’re happy to sit down and give you a free consultation.