Running Water In Plastic Septic Tanks: How Much Is Too Much?

Understanding the water level in your septic tank is crucial for maintaining your home's septic system. A high water level in your septic tank can cause issues such as hydraulic overload, sewage backups, and reduced microbial activity. To prevent problems, it is essential to ensure that the water level stays below a certain point. The size and capacity of a septic tank depend on factors such as the number of bedrooms, square footage of living space, and local regulations. The average residential septic tank can hold around 950 gallons of water, with an average person using 50-75 gallons per day. To maintain optimal water levels, it is crucial to avoid excessive water usage and be mindful of what goes down your drains.

Septic tank capacity and water usage

The capacity of a septic tank determines how much waste it can hold before it needs to be pumped. The size and capacity of a septic tank are influenced by factors such as the number of bedrooms in a home, the square footage of living space, and local regulations. The average residential septic tank can hold around 950 gallons of water, with an average person using 50-70 gallons per day. For a family of four, this translates to 200 gallons per day, and the tank will be full within 7-10 days.

To determine the daily volume of wastewater your septic tank needs to handle, multiply the number of people in your household by 95 litres. For example, a four-person household would require a septic system that can support 380 litres per day.

It is important to avoid excessive water usage to maintain optimal water levels in your septic tank. This includes spacing out water usage and avoiding running multiple high-water-consuming appliances simultaneously, such as washing machines and dishwashers. Additionally, be mindful of what goes down your drains, and avoid flushing non-biodegradable items, excessive grease, or chemicals that can harm the septic system.

The type of soil on your property also impacts the size of your septic system design. The drain field, or leach field, is responsible for the final stage of wastewater treatment, filtering the effluent before it re-enters the groundwater. Different soil types have varying abilities to absorb and filter effluent, so this will influence the size of your drain field and, indirectly, the size of your septic tank.

While a septic tank that is too large may not be an issue, a tank that is too small can cause problems such as bad smells, flooding, and blockages. An undersized septic tank can lead to wastewater backup, with warning signs including strong odours, water backing up, and an increase in water consumption.

Maintaining optimal water levels

Understanding Water Usage: It is important to understand the water usage patterns in your household. The number of people in your home directly impacts the water usage and, consequently, the load on your septic tank. As a rule of thumb, each person is estimated to use around 50 to 150 gallons of water per day. This estimation will help you determine the capacity required from your septic system.

Selecting the Right Tank Size: Choosing the right size for your plastic septic tank is critical. The size should be based on the number of bedrooms in your home, the square footage of living space, local regulations, and the number of individuals residing in the house. A tank that is too small for your household can lead to frequent problems, including unpleasant odours, flooding, and blockages. On the other hand, a larger tank may be more expensive but can provide a safer and more reliable option in the long run.

Spacing Out Water Usage: To maintain optimal water levels in your plastic septic tank, it is advisable to space out water usage throughout the day. Avoid running multiple high-water-consuming appliances simultaneously, such as washing machines and dishwashers. By staggering their usage, you can prevent overloading your septic system during periods of high water usage.

Conserving Water: Water conservation plays a vital role in maintaining optimal water levels in your plastic septic tank. Simple practices such as repairing dripping faucets, avoiding long showers, and running washing machines and dishwashers only when they are full can significantly reduce water consumption. Additionally, consider installing water-saving features in your faucets, showerheads, and toilets to further reduce water usage.

Monitoring Water Levels: Regularly monitor the water levels in your plastic septic tank to ensure they stay below a certain point. A high water level in your septic tank can indicate issues such as hydraulic overload, sewage backups, and reduced microbial activity. Keep an eye on the scum and sludge layers and consider pumping out your tank when the bottom of the scum layer is within 3 inches of the outlet device or when the top of the sludge layer is within 12 inches of the outlet device.

Water conservation methods

Water conservation is essential to maintaining a healthy septic system and preventing costly repairs. Here are some methods to conserve water and maintain your plastic septic tank:

Understand Your Septic System

Knowing how your septic system works is crucial for effective water conservation. The wastewater generated in your home flows into the septic tank, where solids settle at the bottom, forming a layer of sludge. Grease and lightweight particles float to the top, creating a scum layer. The remaining liquid wastewater, or effluent, exits the tank and enters the drain field for further treatment in the soil. The septic tank's role is to retain solids and allow only the effluent to move on for treatment.

Minimize Water Consumption

Reducing water usage is key to preventing overloading your septic system. This can be achieved by adopting simple practices such as fixing leaky faucets and toilets, installing low-flow faucet aerators and showerheads, and running washing machines and dishwashers only when they are fully loaded. Spread out water usage throughout the day, and avoid running multiple high-water-consuming appliances simultaneously.

Proper Maintenance

Regular maintenance is essential to prolonging the life of your septic system. Have your system inspected annually and the tank pumped out every 2-5 years by a professional contractor. Keep a detailed record of repairs, pumpings, inspections, and permits. Ensure you understand the basic functioning of your septic system and the factors that affect water levels, such as the number of occupants and the size of your home.

Avoid Harmful Substances

Be mindful of what goes down your drains. Avoid flushing non-biodegradable items, excessive grease, oils, fats, butter, wax, coffee grounds, and chemicals. These can harm the healthy bacteria in your septic tank and drain field, which are essential for breaking down organic matter. Use household chemicals sparingly and dispose of leftover hazardous chemicals at an approved waste collection center.

Divert Excess Water

Direct rainwater drainage systems, such as roof drains and sump pumps, away from your drain field area. The field receives enough water from regular household use, and excess water can slow down or stop the wastewater treatment process.

By following these water conservation methods, you can help maintain a balanced water level in your plastic septic tank, prevent potential issues, and extend the life of your septic system.

Potential issues with high water levels

The water level in your septic tank is essential to maintaining your home's septic system. A high water level in your septic tank can indicate various issues and might be a cause for concern. Here are some potential issues with high water levels:

Hydraulic Overload:

Hydraulic overload occurs when the incoming wastewater exceeds the tank's capacity to release the effluent into the drain field. This condition puts undue stress on the tank and drain field and can lead to backups in your home's plumbing. The quick rise in water levels can cause blockages and flooding, which is a common issue when a septic tank is too small for a home.

Sewage Backups:

High water levels can push solids and scum back into the septic tank filter, leading to clogs and sewage backups in your house. This can create an unsanitary and unpleasant living environment. The backups can also cause damage to your home's plumbing system.

Reduced Microbial Activity:

The microorganisms in the septic tank play a crucial role in breaking down solids. High water levels can negatively affect microbial activity by diluting the microbial population, hindering their ability to decompose waste effectively. This can lead to a build-up of solids in the tank, reducing its capacity to process wastewater.

Environmental Contamination:

If the septic tank is full, the effluent might leak into the surrounding environment, causing contamination. This can happen due to cracks or damage to the tank or the pipe connecting the tank to the drain field. It is essential to regularly inspect and pump your septic tank to prevent such issues.

Increased Water Usage:

High water levels in the septic tank can be caused by excessive water usage, such as running multiple high-water-consuming appliances simultaneously (washing machines, dishwashers). Spacing out water usage throughout the day and being mindful of what goes down your drains can help prevent overloading the septic system.

Selecting the right septic tank size

Number of Bedrooms and Occupants:

The number of bedrooms in a home is a critical factor in determining septic tank size. This is because the number of bedrooms provides an estimate of the potential occupancy, which directly impacts the amount of wastewater generated. A 3-bedroom house, for instance, typically requires a 1000-1250 gallon septic tank, considering moderate water usage.

Daily Water Usage:

Estimating the daily water usage per person is essential when selecting a septic tank size. A good rule of thumb is to assume each person uses about 50-75 gallons of water per day, which translates to roughly 150-250 gallons per bedroom per day. However, actual usage may vary depending on lifestyle and water-saving habits.

High-Water Usage Appliances:

Consider any appliances that use a lot of water, such as dishwashers or washing machines. Each of these appliances will require additional capacity in your tank. For each high-water usage item, it is recommended to add an extra 250 gallons to your tank size.

Soil Type:

The soil type in your drain field, also known as the leach field, is critical in determining septic tank size. The drain field is responsible for the final stage of wastewater treatment, where it filters the effluent (liquid waste) from the septic tank before it re-enters the groundwater. Different soil types have varying absorption and filtration rates, so understanding your soil conditions ensures that the entire system works efficiently.

Local Regulations:

Local building regulations and codes play a significant role in septic tank sizing. These regulations often specify minimum septic tank measurements, requirements, and restrictions based on property size and soil type. It is important to consult your local environmental department and building offices to ensure compliance and avoid penalties.

Future Expansions:

If you anticipate future expansions, such as adding more rooms or family members, it is wise to invest in a septic tank with additional capacity. By considering your future needs, you can reduce the risk of costly upgrades later.

In summary, selecting the right septic tank size involves considering factors such as the number of bedrooms, occupants, daily water usage, high-water usage appliances, soil type, local regulations, and future expansions. By taking these factors into account, you can ensure your septic system operates efficiently and effectively.

Frequently asked questions