What kind of Sequim septic systems are there for homes with private septics? There are many different kinds, and it can be confusing if you are a buyer. Here is a complete list of the various kinds of Sequim septic systems you can be required to have.
Sequim Septic Systems
- Sequim Septic Systems – Gravity
Consists of a septic tank which flows effluent by gravity to a distribution box (D-box); one or more connections to this D-box drain into trenches typically filled with gravel. Only a small part of the drainfield is used at any one time. Requires a minimum of 48 inches of permeable soil above a restrictive layer to be used on new construction. Least amount of maintenance required of any system type but requires the greatest soil depth in order to provide adequate treatment of the effluent. - Sequim Septic Systems – Gravity with Pump
Gravity with the addition of a pump tank. Allows the drainfield to be located upslope from the septic tank. In addition, the drainfield is dosed which permits intermittent resting of the drainfield between doses. Additional maintenance to the pump tank and float switches are necessary. - Sequim Septic Systems – Pressure Distribution
Consists of a septic tank and pump tank with pressurized lines leading to individual trenches. This allows dosing of the drainfield and use of the entire drainfield at once. Requires at least 30-36 inches of permeable soil above a restrictive layer to be used on new construction. Maintenance required to assure the orifices do not plug over time. - Sequim Septic Systems – Mound
A treatment-based system consisting of pressurized lines lying in a sand bed mounded above the original soil surface. Requires at least 18 inches of permeable soil above a restrictive layer to be used on new construction. This system type has allowed construction on sites previously thought unsuitable due to lack of soil depth. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Subsurface Mound
A treatment-based system consisting of pressurized lines lying in a sand bed mounded above the original soil surface. Requires at least 18 inches of permeable soil above a restrictive layer to be used on new construction. This system type has allowed construction on sites previously thought unsuitable due to lack of soil depth. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – The Sand Filter – Pressure Distribution
Consists of sand placed in a watertight box built into the soil. Effluent is spread evenly over the surface of the sand via a pressurized network. The sand layer treats the effluent and is collected in the bottom of the filter box from which it is then pumped to a drainfield. The drainfield in this case is a pressure distribution system, which finishes the treatment process and then disposes of the wastewater. Requires at least 18 inches of permeable soil above a restrictive layer to be used on new construction. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Sand Filter – Gravity
Consists of sand placed in a watertight box built into the soil. Effluent is spread evenly over the surface of the sand via a pressurized network. The sand layer treats the effluent and is collected in the bottom of the filter box from which it then is pumped or gravity fed to a gravity drainfield. Requires at least 24 inches of permeable soil above a restrictive layer to be used on new construction. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Sand Filter – Mound
Consists of sand placed in a watertight box built into the soil. Effluent is spread evenly over the surface of the sand via a pressurized network. The sand layer treats the effluent and is collected in the bottom of the filter box from which it then is pumped to a mound. The mound finishes the treatment process and then disposes of the treated wastewater. Used in situations where minimal soil exists, at least 12 inches of soil is required on at least 5 acres. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – The Sand Filter – Subsurface Mound
Consists of sand placed in a watertight box built into the soil. Effluent is spread evenly over the surface of the sand via a pressurized network. The sand layer treats the effluent and is collected in the bottom of the filter box from which it then is pumped to a subsurface mound. The mound finishes the treatment process and then disposes of the treated wastewater. Used in situations where the soil condition does not permit adequate treatment of the wastewater before disposal. The addition of the sand filter may be used to help mitigate other shortcomings of a particular site. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Sand Lined Bed
A treatment-based system consisting of pressurized lines lying in a sand bed buried into the ground. The sizing of drainfield laterals is equal to a standard system. Used in situations where the soil is deep but very porous thus lacking treatment capability. This occurs in areas where soils are very gravelly or extremely gravelly in nature. The system is easier to construct than sand lined trenches but takes up more area than a subsurface mound. It may be the system of choice where there are soil inconsistencies such that a smaller subsurface mound may not have sufficient contact with the more gravelly soil portions of the site. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Sand Lined Trench
A treatment-based system consisting of pressurized lines lying in sand filled trenches. The sizing of drainfield laterals is equal to a standard system. Used in situations where the soil is deep but very porous thus lacking treatment capability. This occurs in areas where soils are very gravelly or extremely gravelly in nature. Can be used as an alternative to a mound or sand filter system. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Sand Filter – Lined Bed
Consists of a sand filter followed by a sand lined bed system. The addition of the sand filter may be used to help mitigate other shortcomings of a particular site. See #10 for more details. - Sequim Septic Systems – Sand Filter – Lined Trench
Consists of a sand filter followed by a sand lined trench system. The addition of the sand filter may be used to help mitigate other shortcomings of a particular site. See #11 for more details. - Sequim Septic Systems – The Upflow Sand Filter (Glendon Biofilter)
Consists of different layers of sand and gravel placed in a watertight box built into the soil. Effluent is pumped into the bottom of the filter and allowed to wick itself up through the sand and over the rim of the box into the soil. Several boxes or pods may be used to accommodate varying site conditions and number of bedrooms. A splitter along with a timing device is used to assure even flow to all pods. This system can be used in situations where a lot has 18 inches of soil and only12 inches if 5 acres or greater. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – Aerobic Treatment Unit (ATU) – Gravity
Consists of a watertight tank with an aeration chamber where sewage and microorganisms come in contact with each other in the presence of dissolved oxygen. Blowers, compressors or air pumps supply the air. The treated effluent is then drained into a conventional gravity drainfield. To meet the highest treatment standards a disinfection unit must be part of the device to reduce the bacteriological counts. With disinfection the system could be used on a site with only 24 inches of soil. Without disinfection the system would require at least 4 feet of soil. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – ATU – Mound
Consists of a watertight tank with an aeration chamber where sewage and microorganisms come in contact with each other in the presence of dissolved oxygen. Blowers, compressors or air pumps supply the air. The treated effluent is then pumped into a mound system for final treatment and disposal. This system works well in combination as the ATU lowers waste strength but still produces high bacteriological counts, which are eliminated in the mound. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – ATU – Pressure Distribution
Consists of a watertight tank with an aeration chamber where sewage and microorganisms come in contact with each other in the presence of dissolved oxygen. Blowers, compressors or air pumps supply the air. The treated effluent is then pumped into a pressure distribution system for final treatment and disposal. To meet the highest treatment standards a disinfection unit must be part of the device to reduce the bacteriological counts. With disinfection the system may be used with as little as 18 inches of soil. Without disinfection the system requires no less than 30 inches of soil. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time. - Sequim Septic Systems – ATU – Sand Filter
Consists of a watertight tank with an aeration chamber where sewage and microorganisms come in contact with each other in the presence of dissolved oxygen. Blowers, compressors or air pumps supply the air. The treated effluent is then pumped into a sand filter for further treatment. A pressure distribution system would then dispose of the treated wastewater. To meet the highest treatment standards a disinfection unit must be part of the device to reduce the bacteriological counts. With disinfection the system may be used with as little as 18 inches of soil. Without disinfection the system requires no less than 30 inches of soil. The complexity of this system and the situations in which it is used requires periodic maintenance and proper operation to assure continued performance standards be met over time.
Sequim Septic Systems
If you are buying vacant land and installing your private septic system, the cost can vary from a simple conventional system that may cost $7,000 to an expensive pressurized mound system that could cost $18,000 or more. If you’re buying an existing home, Sequim septic systems still need to be inspected and approved on an annual basis.
Last Updated on September 19, 2019 by Chuck Marunde
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