When it comes to septic systems, understanding the volume of sewage produced per person is essential—not just for homeowners looking to maintain their systems, but also for professionals who install and design these systems. The amount of sewage a person generates directly impacts the size and design of the septic tank, its longevity, and overall performance.
In this blog, we’ll explore how much sewage is produced per person, the factors that influence these figures, and why this information is critical for those involved in the installation, maintenance, and management of septic tanks.
What Is Sewage and Why Does It Matter?
Sewage refers to the wastewater and waste products from households or commercial establishments that flow through plumbing systems. It typically includes water from toilets, sinks, showers, bathtubs, dishwashers, washing machines, and other sources. In rural or off-grid areas, where homes are not connected to a municipal sewage system, a septic tank is commonly used to treat and dispose of this wastewater.
The design and size of the septic tank are directly tied to the volume of sewage produced. If a septic tank is too small for the amount of sewage generated, it can quickly become overwhelmed, leading to clogs, backups, and potential contamination of the surrounding environment.
So, understanding how much sewage is produced per person in a household is the first step toward ensuring the septic system is properly sized and that it functions efficiently over time.
How Much Sewage Is Produced Per Person?
On average, each person in a household generates between 50 to 100 gallons of wastewater per day. This can vary based on a number of factors, including lifestyle, water usage habits, and the efficiency of appliances. Let’s break down these figures to understand where this water comes from and why it matters for septic tank sizing.
Toilets:
The largest contributor to household sewage is the water used in toilets. According to the U.S. Environmental Protection Agency (EPA), the average toilet flush uses 1.6 gallons of water for newer models, but older toilets can use significantly more—up to 7 gallons per flush. If you consider that an average person flushes the toilet about five times per day, that’s about 8 to 40 gallons per person per day just from toilet use alone. This is why maintaining an efficient, low-flow toilet is essential for reducing water consumption and minimizing the strain on your septic system.
Showers and Baths:
Another major contributor is water used for personal hygiene. On average, a shower uses between 2 and 5 gallons of water per minute, depending on the showerhead’s efficiency. A typical shower lasts about 8 minutes, resulting in roughly 16 to 40 gallons of water per shower. If each person in the household showers once a day, this adds another 16 to 40 gallons of wastewater per person.
Bathtubs, though less common than showers in terms of frequency, generally use more water. A standard bathtub can hold anywhere between 30 to 50 gallons of water, but this is usually a once-a-day activity in most households.
Sinks and Faucets:
Water used in kitchen sinks, bathroom sinks, and other faucets is another significant contributor to household sewage production. The average faucet flows at a rate of about 2.2 gallons per minute, but this varies with the type of faucet and its age. A typical person might use the faucet for washing hands, brushing teeth, or cleaning dishes, adding an average of 5 to 15 gallons of wastewater per day, depending on water usage habits.
In the kitchen, dishwashers can add significant amounts of water to the overall sewage volume. Modern dishwashers tend to be more efficient, using around 3 to 5 gallons per load. For those without dishwashers, manual washing can use 20 to 30 gallons per load or more, depending on the style and frequency of cleaning.
Laundry:
Laundry is another considerable source of sewage. A standard washing machine uses around 15 to 45 gallons of water per load depending on the model, size, and efficiency of the appliance. A typical person might do about 1 to 2 loads of laundry per week, adding around 2 to 10 gallons of wastewater per person per day. For families with larger laundry needs, this volume can increase.
Factors That Affect Sewage Production
While we can use averages to estimate how much sewage a person produces, there are several factors that can affect the amount of wastewater generated in any given household. Let’s take a closer look at these factors:
Water Usage Habits:
The more water a person uses, the more sewage they will generate. For instance, individuals who take long showers, use water-intensive appliances, or wash clothes frequently will produce more wastewater than those who are conscious about water conservation. Installing low-flow faucets, showers, and toilets can reduce sewage production and help minimize the strain on a septic system.
Household Size:
Naturally, the more people in a household, the more sewage will be produced. A family of four will generate more wastewater than a single person living alone. This is important when designing and installing septic systems, as the capacity of the tank and drain field must be able to accommodate the increased volume.
Age and Type of Plumbing Fixtures:
Older homes may have plumbing fixtures that use more water compared to modern, water-efficient fixtures. For example, older toilets often use 5 to 7 gallons per flush, while newer models use only 1.6 gallons. Similarly, old faucets and showerheads may flow at rates higher than the 2.2 gallons per minute typical of newer models. Upgrading fixtures can significantly reduce sewage output, improving the overall efficiency of the septic system.
Lifestyle and Activity Level:
The lifestyle of individuals in a household can affect the amount of water and sewage produced. For example, households with children or multiple adults may use more water for daily activities such as laundry, dishes, and baths. People who work from home may also use more water for washing hands, cooking, and cleaning.
Seasonal Changes:
Water usage tends to fluctuate depending on the time of year. For instance, people may take more showers in the summer when it’s hotter and they’re more active, while winter months might see less frequent showers but more water use for heating, washing dishes, and laundry. These seasonal variations should be considered when assessing sewage production.
Why Understanding Sewage Volume is Crucial for Septic Tank Installation
Knowing how much sewage is produced per person is essential when it comes to septic tank sizing and installation. A tank that is too small for the household’s sewage output will quickly fill up, causing slow drainage, clogs, and even system failure. Conversely, an oversized septic tank can be inefficient and costly to install.
Here are a few reasons why understanding sewage production matters:
Sizing the Tank Properly: By calculating the volume of sewage generated by the people in the household, you can ensure the septic tank is appropriately sized to handle that volume. In general, septic tank sizes range from 750 to 1,500 gallons, with the most common size being 1,000 gallons for a household of 4 people.
Preventing Overflows and Backup: Properly sized septic tanks can handle the waste generated without overflowing or causing backups. Regular maintenance, such as pumping the tank every 3-5 years, is also necessary to keep the system working efficiently.
Designing the Drain Field: The drain field, where treated wastewater is released into the soil, must also be appropriately sized based on the volume of sewage produced. A system that is too small for the household’s needs can lead to contamination of groundwater and soil.
Understanding how much sewage is produced per person is critical for anyone involved in the installation, maintenance, or management of septic systems. On average, each person produces around 50 to 100 gallons of wastewater per day, but this can vary depending on water usage habits, lifestyle, and the efficiency of appliances.
By accurately estimating sewage production and sizing septic tanks accordingly, professionals can ensure the system functions efficiently, preventing clogs, backups, and environmental contamination. Homeowners, in turn, can optimize their water usage to reduce costs, conserve resources, and extend the life of their septic system.
If you’re installing or maintaining a septic system in 2025, understanding the volume of sewage generated in a household will be one of the most important factors in ensuring your system is efficient, reliable, and environmentally friendly.
