Septic System Designs

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Perc and mantle is the test of the soils, the septic design is performed after.

There are many different styles of designs and every design is custom to the property and are based upon the rules of what is allowable in your County.

Once a design is completed it is ready to apply for the installation permit and to go out for bid for you to choose a contractor to install it.

A conventional septic system is one of the most common types of onsite wastewater treatment systems. It uses a septic tank and a drain-field, also called leach lines, to treat and disperse wastewater safely into the soil.

Wastewater from the home first flows into the septic tank, where solids settle to the bottom and natural bacteria begin breaking down the waste. The liquid effluent then flows by gravity into a series of narrow underground trenches. These trenches are partially filled with washed gravel or crushed stone and contain perforated pipe that evenly distributes the effluent into the surrounding soil.

The soil provides the final stage of treatment as the wastewater slowly filters through it. For this type of system to work properly, the drain-field must be carefully sized and designed based on the soil’s percolation rate, site conditions, and local health department requirements.

A conventional septic system typically includes two main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the treatment process. 
2. Leach Lines / Drain-Field
   Distributes treated liquid effluent into the soil for final filtration and absorption. 

To keep the system working properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, and system condition. Regular maintenance helps protect the drain-field, supports proper bacterial action, and extends the life of the system.

A pump-to-gravity septic system is similar to a conventional gravity septic system, but it includes an additional pump tank and pump to move wastewater effluent to the drain-field.

This type of system is typically used when the property conditions do not allow effluent to flow by gravity from the septic tank to the leach field. This can happen when the drain-field is located uphill, farther away, or at an elevation that requires mechanical assistance.

Wastewater first flows from the home into the septic tank, where solids settle and natural bacteria begin breaking down the waste. The liquid effluent then moves into a separate pump chamber. From there, a pump sends the effluent to standard leach trenches, where it is distributed through perforated pipe into the surrounding soil for final treatment and absorption.

A pump-to-gravity system typically includes these main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the treatment process. 
2. Pump Chamber Tank
   Collects liquid effluent from the septic tank before it is pumped to the drain-field. 
3. Pump and Control Panel
   The pump moves effluent to the leach field, while the control panel manages pump operation and may include alarms to alert the homeowner if there is a problem. 
4. Leach Lines / Drain-Field
   Distributes the effluent into the soil for final filtration and absorption. 

To keep the system operating properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, and system condition. The pump system should also be inspected periodically to confirm the pump, floats, alarms, and control panel are working correctly. Regular maintenance helps protect the drain-field and extends the life of the system.

A deep trench septic system is similar to a conventional gravity septic system, but the leach trenches are installed at a greater depth.

Because the trenches are deeper, they can often provide more absorption area in a shorter trench length. This means less total lineal footage may be needed compared to a standard leach field. Deep trench systems are commonly used on smaller lots or properties where space is limited, provided the soil conditions are suitable for deeper trench construction.

Wastewater first flows from the home into the septic tank, where solids settle and natural bacteria begin the treatment process. The liquid effluent then flows by gravity into the deep leach trenches, where it is distributed into the surrounding soil for final treatment and absorption.

If a standard leach field can fit within the designated area and the site conditions allow it, a standard system is usually preferred. A deep trench system is typically considered when additional depth helps meet design requirements while working within the available space.

A deep trench septic system typically includes two main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the treatment process. 
2. Leach Lines / Drain-Field
   Distributes liquid effluent into deeper trenches, where the surrounding soil provides final filtration and absorption. 

To keep the system operating properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, and system condition. Regular maintenance helps protect the drain-field, supports proper bacterial action, and extends the life of the system.

A pressure dose septic system is used when site or soil conditions require more controlled distribution of effluent into the leach field. This type of system may be recommended when soils absorb wastewater either very quickly or very slowly.

Unlike a standard gravity system, a pressure dose system uses a pump chamber and pump to send effluent to the drain-field under pressure. The leach field is designed somewhat like an underground sprinkler system, allowing the effluent to be distributed evenly throughout the entire drain-field at scheduled intervals.

A control panel manages the pump and dosing schedule. The timing and volume of each dose are based on the system design, soil conditions, and local requirements. This controlled dosing helps prevent overloading one area of the drain-field and allows the soil to receive wastewater in measured amounts.

Please note: In Nevada County, this type of system requires annual maintenance and monitoring.

A pressure dose leach line system typically includes these main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the treatment process. 
2. Pump or Dosing Chamber Tank
   Collects liquid effluent from the septic tank before it is pumped to the drain-field. 
3. Pump and Control Panel
   The pump sends effluent to the leach field under pressure, while the control panel manages the dosing schedule and system operation. 
4. Leach Lines / Drain-Field
   Distributes pressurized effluent evenly throughout the drain-field for final treatment and absorption into the soil. 

To keep the system operating properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, and system condition. In addition, the pump, controls, and filter should be inspected and cleaned annually. The leach field laterals should also be high-pressure flushed annually as part of the required maintenance and monitoring program.

A pressure dose system with capping fill is similar to a standard pressure dose leach line system, but it includes an additional soil cap over the drain-field.

This type of system is typically used when the natural soils on the property are too shallow to provide the required treatment depth. In these cases, suitable soil may need to be brought in, or usable soil from the site may be moved and placed over the leach field to create the proper soil cover required by the system design.

Like a standard pressure dose system, a pump chamber and pump send effluent to the leach field under pressure. The leach field is designed to distribute effluent evenly throughout the entire drain-field at scheduled intervals. A control panel manages the dosing schedule based on the system design, soil conditions, and local requirements.

The added capping fill helps provide the soil depth needed for proper wastewater treatment and absorption. The amount and type of capping fill required can vary significantly from one property to another, depending on available onsite soils, design requirements, soil quality, and local material availability.

Please note: In Nevada County, this type of system requires annual maintenance and monitoring.

A pressure dose system with capping fill typically includes these main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the treatment process. 
2. Pump or Dosing Chamber Tank
   Collects liquid effluent from the septic tank before it is pumped to the drain-field. 
3. Pump and Control Panel
   The pump sends effluent to the leach field under pressure, while the control panel manages the dosing schedule and system operation. 
4. Leach Lines / Drain-Field
   Distributes pressurized effluent evenly throughout the drain-field for final treatment and absorption. 
5. Capping Fill
   Provides additional soil cover over the leach field where natural soil depth is limited. 

To keep the system operating properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, and system condition. The pump, controls, and filter should be inspected and cleaned annually, and the leach field laterals should be high-pressure flushed annually as part of the required maintenance and monitoring program.

A pretreatment septic system, also called an advanced treatment system, is used when site conditions require wastewater to receive additional treatment before it reaches the final leach field or dispersal area.

These systems are commonly used where soils are shallow, limited, fast-draining, slow-draining, or where the site needs extra protection before treated effluent is dispersed into the ground. Instead of sending septic tank effluent directly to a standard leach field, the wastewater first passes through an approved treatment component, such as a treatment pod, sand filter, aerobic treatment unit, biofilter, or other manufacturer-approved pretreatment system.

Wastewater first flows from the home into the septic tank, where solids settle and the initial treatment process begins. From there, effluent is typically pumped or dosed into the pretreatment unit. After the additional treatment step, the treated effluent is sent to the final dispersal area, which may be designed as a pressure dose leach field, drip dispersal field, mound, sand-based system, or other approved drain-field design.

Please note: Pretreatment systems require annual maintenance and monitoring.
In Nevada County, pressure dose and treatment systems are required to be monitored annually by a Certified Septic Service Provider. These systems also generally require an annual operating permit and recorded maintenance/monitoring agreement. Maintenance requirements are based on the specific system manufacturer, the approved design, the county permit conditions, and the manufacturer’s operation and maintenance manual. 

Pretreatment systems used in our area may include:

AdvanTex, sand filter, Hoot, Infiltrator EcoPod, Eljen, Presby, Ecoflo, and Prelos.

A pretreatment septic system typically includes these main components:

1. Septic Tank
   Holds wastewater, separates solids, and begins the initial treatment process. 
2. Pump or Dosing Chamber Tank
   Collects effluent and sends it to the pretreatment unit or final dispersal area as required by the design. 
3. Control Panel or Panels
   Manage pumps, floats, alarms, dosing schedules, and system operation. Some advanced systems may have more than one control panel. 
4. Pretreatment Unit
   Provides additional treatment before effluent reaches the leach field. This may be a pod, sand filter, aerobic treatment unit, biofilter, textile filter, geotextile sand filter, or other approved treatment component. 
5. Leach Lines / Drain-Field / Drip Field
   Receives treated effluent for final dispersal into the soil. The final field design depends on the soil conditions, slope, available area, depth to limiting layer, and local requirements. 

To keep the system operating properly, the septic tank should generally be pumped every three to five years, depending on household size, usage, tank size, and system condition. The pretreatment unit, pumps, controls, filters, alarms, and dispersal field components should be inspected and maintained at least annually, or more often if required by the manufacturer, permit, or service manual.

AdvanTex is an advanced treatment system made by Orenco. It uses a textile filter treatment pod to improve effluent quality before the wastewater is sent to the final dispersal area. Orenco’s maintenance materials state that residential AdvanTex systems require periodic servicing, with annual visits after the initial startup service schedule for common residential models. 

A sand filter system uses a specially designed sand media bed or box to further treat septic tank effluent before it reaches the final drain-field. The effluent is typically pumped or dosed over the sand filter, where physical, biological, and chemical processes help improve treatment quality before final dispersal. Sand filter systems commonly include a septic tank, pump chamber, sand filter, and drain-field or other disposal component. 

Hoot systems are aerobic treatment units. They use oxygen and naturally occurring microorganisms to help break down and treat wastewater before it is discharged to the final dispersal system. Hoot manuals emphasize that service must be performed by trained or certified service representatives, and some Hoot documentation requires maintenance by a qualified professional as often as every six months, depending on the model and local rules. 

The Infiltrator EcoPod is a fixed-film advanced wastewater treatment unit. It provides additional treatment before effluent is sent to the final dispersal area. Infiltrator’s product documentation identifies the EcoPod-N as an advanced wastewater treatment unit and provides separate installation, operation, and maintenance manuals. The system may also include separate components such as dosing equipment or drip irrigation, which have their own maintenance requirements. 

Eljen GSF systems use a geotextile sand filter design. The system is commonly used where sites have space limitations, high groundwater, poor soils, or other challenging conditions. Eljen describes the GSF as a passive advanced treatment system using its Bio-Matt treatment process. Nevada County-specific Eljen documentation also references 12-month inspections and notes that additional monitoring and maintenance may be required by county rules. 

Presby systems, now commonly associated with Infiltrator’s Enviro-Septic / Advanced Enviro-Septic product line, combine treatment and dispersal using proprietary pipe and system sand. Owner and design materials describe the system as rows of treatment pipe with a layer of system sand, preceded by a septic tank or equivalent primary treatment system. 

Ecoflo is a compact biofilter system by Premier Tech. It uses a natural filtering media, commonly coconut husk fragments or a combination of coco and peat moss, to treat wastewater before final dispersal. Premier Tech states that Ecoflo systems require annual maintenance to maintain performance and help preserve the filtering media. 

Prelos is an Orenco pressurized liquid-only sewer or processor system. It is not exactly the same type of treatment pod as an AdvanTex, Hoot, or Ecoflo unit, but it may be used as part of engineered wastewater collection, filtration, pumping, or dispersal designs. Orenco describes the Prelos Processor as providing integrated storage, filtration, pumping, and primary wastewater treatment for pressurized liquid-only sewer or dispersal systems. Regular servicing is required to optimize performance and protect public health.