Sand Filter
The sand filter normally has a wall height of approximately 55 inches. In previous years some of the sand filter walls were constructed of concrete blocks, however, solid concrete has been required in more recent years. Where concrete blocks were used it is necessary to give additional support to the walls by the sloping of the earth on the outside. The walls must be maintained in a leak-proof condition at all time. Any backing of earth next to the filter walls should be kept free of weeds. However, it is possible to shrub the area. Where small children are in the area it is wise to place a fence around the sand filter.

Filter Bed
The sand filter bed consists of a bottom 12 inches of rock (# 3 size), covered with 3 inches of pea gravel and the top 30 inches in washed coarse sand. Greases and lints often stop up the surface of the sand and it is necessary to remove the top 4 inches and replace it with new sand when pooling is observed. The surface of the sand filter should be kept free of trash, grass, weeds and must be kept level with a splash block under the outlet line so as to provide an even distribution of the liquid over the entire surface.

Absorption Area
The absorption area, commonly known as the later field, receives the filtered sewage which after passing through the sand filter should be practically clear. It enters into the absorption field though 4 inch piping. An air vent is placed in the discharge line from the sand filter to the lateral field to prevent air-locking. This system does not prevent overflowing of the laterals field but it does prevent the raw sewage from coming to the surface of the ground. This is particularly true where the absorptive ability of the soil is not good. Surface water should not be allowed to stand on the lateral field but should be drained away from the area.

General
It is necessary to consider the sand filter system as an expensive piece of equipment required to be maintained in a good operation condition at all times. Therefore, it is necessary that this system be reviewed at least once every 30 days. The first indication of trouble necessitates your immediate attention. Should your system indicate that it requires attention, contact a certified installed with a local septic system company to visit the site, evaluate the situation and make necessary repairs or adjustments. Generally it is not wise to undertake the corrections yourself nor should you employ a uncertified technician such as a “jack-of-all-trades” or handyman. Untrained persons can cause more damage and unnecessary expenses.

Trouble Check for Sand Filter Systems
Trouble	Probable Cause	Corrective Action
Liquid Standing on filter bed. (ponding)	Sand Dirty	Remove top layer of sand to clean sand, then refill to previous 30 inches.
	Vegetation Growing	Remove all plant life, rake smooth and level. Change sand if necessary.
	Frozen	Break ice and crest with ax, pick, etc.
	Plugged Outlet	Remove breather cap and check for sand, mud, cloth, etc.

Other Topics
Sewage Protection Program | Homeowners Pump & Alarm Check List | Septic Tank Additives Danger in Disguise | Check List for Evaluating Your Septic System | Corrective Action for a Failing Septic System | Why Systems Fail

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