When it comes to running a household, septic tank size is key. Many homeowners overlook the importance of sizing their septic system and end up with maintenance issues and costly repairs.
A properly sized septic tank means efficient waste management, no environmental hazards, and longer system life.
In this post, we will go into the factors that determine septic tank size, household size, water usage, and local regulations. By knowing these you can make an informed decision and avoid the common mistakes of how big are septic tank is.
What Affects Septic Tank Size?
Number Of Bedrooms: This is usually the first factor in determining septic tank size requirements. Each bedroom adds 150-200 gallons to the tank’s needed capacity since it’s potential occupancy.
Daily Water Usage: Your household’s water habits play a big role. More water use means you’ll need a bigger septic tank to handle the extra water.
Household Size: The number of people living in your home affects the septic tank size. More people means more waste, so you’ll need a bigger tank to process it.
Local Regulations: Building codes and health department rules in your area may require minimum septic tank sizes based on various factors. Always check local rules before you decide on a tank size.
Soil Type And Percolation Rate: The soil’s ability to absorb and filter wastewater affects the overall septic system design, including tank size. Poor drainage means you may need a bigger tank.
Type Of Septic Tank: Different materials like concrete, plastic, or fiberglass can affect the tank’s dimensions and capacity. Each type of septic tank has its pros and cons.
Future Expansion Plans: If you’re thinking of adding to your home later, it’s smart to factor in a bigger septic tank size now. This will save you money and hassle later.
Appliances And Fixtures: Water-hungry appliances like garbage disposals or whirlpool tubs may require a bump in your septic tank cap to handle the extra load they put on the system.
Septic Tank Depth: Not directly related to capacity, the depth of your tank can affect its performance and lifespan. Proper depth helps maintain the right temperature for bacteria to work.
Standard Septic Tank Sizes
Here’s a breakdown of standard septic tank sizes:
500-Gallon Tanks
These are the smallest tanks available. Most people ask, Is a 500-gallon septic tank big enough? Usually no for a full-time residence. They’re only good for very small homes or cabins with very little water usage.
750-Gallon Septic Tank
This is the minimum for a small home with one or two bedrooms. It’s a step up from the 500-gallon concrete septic tank dimensions but still on the smaller side for most households.
1000-Gallon Septic Tank
A popular choice for many homes. Is a 1000-gallon septic tank big enough? For many three-bedroom homes, it’s the sweet spot. The 1000-gallon septic tank dimensions vary but they’re usually about 8-9 feet long, 5-6 feet wide, and 5-6 feet tall.
1250-Gallon Septic tank
This size has a bit more capacity than the 1000-gallon. Good for larger three-bedroom homes or smaller four-bedroom homes with average water usage.
1500-Gallon Septic Tank
Good for larger homes with four or more bedrooms. The dimensions of a 1500-gallon septic tank are usually 12 feet long, 6 feet wide, and 6 feet tall.
1000-Gallon Concrete Septic Tank
These are durable and long-lasting. The 1000-gallon concrete septic tank dimensions are similar to the plastic ones but may vary slightly due to wall thickness.
Larger Tanks
For very large homes or high water usage, tanks of 2000 gallons or more are available. These aren’t common for residential use but sometimes necessary.
How To Calculate The Right Size Of A Septic Tank?
Calculating the right size of your septic tank is a bit of a process. Start by considering the number of bedrooms in your home, that’s what most regulations use to estimate occupancy.
Local regulations will have minimum sizes based on bedroom count. Then factor in your actual household size and daily water usage. A standard septic tank for residential use is usually 750 to 1,500 gallons.
Soil type and percolation rate in your area will also come into play. For a more exact calculation, consider hiring a professional who can assess your specific situation. They’ll take into account all those factors plus any unique aspects of your property to recommend the right septic tank size for you.
What Is The Average Septic Tank Cost?
The average septic tank cost is all over the place depending on size, material, and location. You’re looking at $3,000 to $10,000 for a full system installation.
Concrete tanks, including round concrete septic tanks, fall in the middle of that range. Septic tank size and price are closely related - bigger tanks cost more.
For example, a 1000-gallon tank might be $2,000-$3,000 and a 1500-gallon tank could be $4,000-$5,000. Don’t forget to add in installation costs and any expenses to meet local septic tank codes.
If you’re looking at different septic tank shapes or need to add to an existing septic system, costs will go up. Get multiple quotes and check local codes.
How To Measure The Septic Tank Sizes?
Septic tank size varies by tank size and material. Here’s a general guide:
1000-gallon tanks are about 8-9 feet long, 5-6 feet wide, 5-6 feet deep. These are common for most households and fit in average-sized yards.
1500-gallon tanks are 12 feet long, 6 feet wide, 6 feet deep. Good for bigger homes or high water usage families.
750-gallon tanks are 7-8 feet long, 5-6 feet wide, 5 feet deep. Good for smaller homes or vacation properties.
Tank shape matters too. While most are rectangular, some are oval or round which affects the footprint.
Concrete tanks have thicker walls so they are slightly bigger than plastic or fiberglass tanks of the same size.
Don’t forget to add space for the tank’s access ports and risers which extend above the tank’s main body for maintenance access.
What Are The Common Misconceptions About Septic Tank Size?
Bigger Is Better: Many think bigger is always better. However, an oversized tank can lead to poor bacteria growth and inefficient waste breakdown.
One Size Fits All: There is no one-size septic tank that fits every home. Your needs depend on household size, water usage, and local regulations.
If You're Careful, Septic Tank Size Doesn’t Matter: Even if you’re careful about what goes down the drain, an undersized tank can still fail and cost you big time.
Water-Saving Fixtures Mean You Can Use A Smaller Septic Tank: While they help, water-saving fixtures don’t dramatically reduce the tank size. Local codes often have minimum size requirements regardless of water usage.
You Can’t Expand Your Septic System Later: Actually, you can, but it’s often more cost-effective to get it right the first time.
Septic Tank Size Is The Only Factor In System Performance: While important, tank size is just one piece of the puzzle. Proper maintenance, soil quality, and drain field size all play a role too.
Maintenance Tips For Optimal Septic Tank Performance
Pump every 3-5 years
Conserve water
Don’t flush non-biodegradable items
Use septic-safe products
Keep heavy vehicles off the drain field
Don’t plant trees near the system
Don’t pour grease or oil down drains
Add bacteria to help break down
Keep records of maintenance and repairs
Don’t use garbage disposal too much
Conclusion
Septic tank size matters for your home’s waste management system. 500 to 1500 gallons and beyond, the right size depends on household size, water usage and local regulations. Bigger isn’t always better, but an undersized tank can cost you big time.
Regular maintenance no matter the size is key to optimal performance. Remember, choosing the right septic tank size is an investment in your property’s health and value.
For septic system selection, installation or maintenance advice, Barnes Sewer and Septic. Our experts will help you get the right size tank for your needs and keep it running. (765) 584-7295 today to discuss your septic tank needs or schedule a consultation.