On-Site Sewage Disposal Program (Septic Systems)

This program deals with the permitting and inspection of on-site sewage disposal systems in Placer County.  This program also involves soils testing to determine the type of on-site sewage disposal system required based on soil conditions.  There are currently three types of systems that we utilize in Placer County.  The decision on which type of system is to be used depends on the soil conditions in the area of a particular parcel.  Placer County also has an experimental program in which there are aerobic treatment units and fixed bed media systems being looked at.

THREE MAIN TYPES OF SEPTIC SYSTEMS

STANDARD SEPTIC SYSTEM (Gravity Flow System):

A standard septic system consists of a septic tank and leachfield.  Wastewater leaves the structure (building) and enters the first compartment of the septic tank.  Heavy solids form sludge in the bottom of the tank, and grease and light material form a scum layer near the top.  The clear zone between the scum layer and sludge layer flows into the second compartment of the septic tank.  Effluent leaves the second compartment and flows to the distribution box at the beginning of the leachfield.  From here, the effluent is distributed by gravity feed to a network of perforated pipes laid in gravel-lined trenches, which comprises the leachfield.  Standard system leachlines are plumbed for serial distribution. 

LOW PRESSURE DOSE SYSTEM:

A low pressure dose septic system consists of a septic tank, pump tank, and leachfield.  Wastewater leaves the structure (building) and enters the first compartment of the septic tank.  Heavy solids form sludge in the bottom of the tank, and grease and light material form a scum layer near the top.  The clear zone between the scum layer and sludge layer flows into the second compartment of the septic tank.  Heavy solids form sludge in the bottom of the tank, and grease and light material form a scum layer near the top.  The clear zone between the scum layer and sludge layer flows into the second compartment of the septic tank.  Effluent leaves the second compartment of the septic tank and enters the pump tank where it is stored.  Effluent is pumped to the leachfield where it is distributed evenly through a network of small diameter pipes under low pressure.  Low-pressure dose systems may be utilized as an alternative for some sites to mitigate the limitations associated with soils and slow permeability.

SAND FILTER SYSTEM:

A sand filter septic system consists of a septic tank, pump tank, sand filter bed, and leachfield.  Wastewater leaves the structure and enters the first compartment of the septic tank.  Heavy solids form sludge in the bottom of the tank, and grease and light material form a scum layer near the top.  The clear zone between the scum layer and sludge layer flows into the second compartment of the septic tank.  Heavy solids form sludge in the bottom of the tank, and grease and light material form a scum layer near the top.  The clear zone between the scum layer and sludge layer flows into the second compartment of the septic tank. Effluent leaves the second compartment of the septic tank and enters the pump tank where it is stored.  From the pump tank, effluent is periodically dosed to the top of the sand filter bed where it trickles through a layer of specialized sand.  Microbes in the sand physically and bacteriologically treat the effluent.  Once the effluent has passed through the sand layer it is collectd in a pump basin where it is pumped to the leachfield.  Effluent is distributed evenly over the entire leachfield using a network of pipes under low pressure.  Sand filter septic systems may be utilized as an alternative for some sites to mitigate the limitations associated with shallow soil depths, soils with rapid permeability, and soils with very slow permeability.     

NOTE:  The sand filter pretreatment system requires annual maintenance by a qualified service provider.  Sand filter systems that were permitted after January 1, 2005 are all under the renewable operating permit program in which operating permits are renewed annually after the annual maintenance have been done.

Adding a Bedroom, Guest House, Second Dwelling ?

If you are planning to add a bedroom, a guest house or a second dwelling on your parcel, please call this office and speak to the District Specialist first.  Your septic system may already be sized to accommodate your plans but you need to ensure that it is so, with the District Specialist.  There may be instances where your septic system may need to be modified or a new system installed to accommodate your plans.  When you call, please have your parcel number (example: 257-060-012-000).  The parcel number works best.  However, if you do not know your parcel number, then please provide the physical address of the parcel.

Adding a Swimming Pool, Pond, Second Driveway or House Addition ?

If you are planning to add a swimming pool to your property or planning to further develop your property  by adding a pond, installing a second driveway or build an out building,  you should be aware of the location of your on-site sewage disposal system.  There are setbacks from structures to the leachfield and septic tank.  Below is the table showing the setbacks.

  SETBACKS

MINIMUM HORIZONTAL SEPARATION DISTANCES (SETBACKS)

Items Requiring Setbacks:	From the disposal field (initial & replacement)	From septic tank and sand filter	Seepage Pits
Ground water Public well Private well Other wells, excluding monitoring wells	150’ 100’ 100’	100’ 50’ 50’	200’ 150’ 150’
Surface public waters         Reservoirs, lakes Year-round streams          and creeks	100’ 100’	100’ 100’	150’ 150’
Intermittent streams, intermittent watercourses or drainage swales	50’	50’	50’
Spring and ponds Upgradient Downgradient	50’ 100’	50’50’ 50’	100’ 100’
Subsurface drains      Curtain drains      Upgradient Downgradient Underdrains	15’ 50’ 20’	15’ 25’ 25’	50’ 50’ 50’
Water supply or irrigation canal               Flat area   Sloping area Upgradient                Downgradient	50’ Clear ROW 100’	50’ Clear ROW 50’	100’ 100’ 100’
ROW means Right of Way * h means the height (in ft) of the cut or escarpment as measured from the toe of the cut or escarpment vertically to the projection of the natural ground slope.
Items Requiring Setbacks:	From the disposal field (initial & replacement)	From septic tank and sand filter	Seepage Pits
Cuts manmade in excess of 2.5 feet (top of downslope cut) or escarpments	*4 x h to maximum of 50’	20’	* 4 x h to maximum of 50’
Property lines       Public water area       Private (domestic) well area	10’ *10’ or 50’	5’ 10’	10’ *10’ or 75’
Foundation lines of any structure Including garages, out-buildings, And **paved surfaces	8’	5’	8’
Swimming pools       In-ground       Above-ground	20’ 5’	20’ 5’	20’ 5’
Water lines (domestic or Non-domestic)	10’	10’	10’
Easements	clear	clear	clear

NOTE:

(a)   Unless otherwise indicated in this table, in the case of flat ground surface and when a different distance is given for upgradient and downgradient, the greater setback distance shall apply.

(b)   Setbacks from streams and creeks shall be measured from back drop-off or mean yearly high water mark, whichever provides the greatest separation distance.

(c)   Crossing of water lines and effluent sewer lines is prohibited.

(d)   The agent shall encourage the placement of septic tanks and other treatment units as close as feasible to the minimum separation from the building foundation in order to minimize possible clogging of the building sewer.

* The 10 ft separation shall apply when adjacent parcels have been developed with structures and domestic water wells.  The 50/75 ft separation shall be used when adjacent parcels have not been developed to the point indicated above.  For major and minor subdivisions, disposal fields may be ten feet from interior property lines in private well areas if a well has been drilled on the affected parcel (See diagram 22) and meets County standards for an approved domestic water supply.  The stricter provision stated above shall apply to parcels adjacent to the subdivision.

** There is no setback requirement for a septic tank to a paved surface.  All septic tanks installed within a paved area shall be constructed in accordance with the provisions of Section 4.45.072 (including having a removable lid), and to withstand any potential load imposed from being under the paved surface.

  RESOURCES

On-Site Sewage Ordinance

On-Site Sewage Program Manual

On-Site Sewage System, Septic As-built Packet

Septic System Consultant List

We have a  Sewage Disposal Contractors List available.  It  is not a recommendation  of any installer or company, nor a guarantee on workmanship.  Rather it is intended as a service to members of the public who will be applying for septic permits, and where a septic installer will be required. 

There are many other answers to Frequently Asked Questions available concerning septic systems.

NOTE:  REMEMBER to check with the Placer County Building Department to determine if your project needs a building permit.

If you are in the incorporated areas of Placer County such as City of Auburn, Rocklin, Roseville, Lincoln, or Loomis, please check with the  building department for that city.