Onsite System Guidance and Regulations


INSTALLATIONS NOT TO BE PERFORMED DURING WET SOIL CONDITIONS!



Install “on contour”:
Drainlines shall be flagged or otherwise marked on precise contours prior to excavation. While the trench bottom must be level, and the piping needs to be level, it is equally important to the proper functioning of the system for the trench to be of uniform depth from end to end and throughout its length. Many installers have concentrated on the trench bottom and ignored the surface contours, resulting in drainlines that are perhaps a foot, and even more, deeper on one end than the other. This will not be acceptable in future installations; drainlines shall be of uniform depth throughout!



Drainline minimum separation distance:
Where sufficient area exists, do not locate drainfield lines 6 feet apart, simply because that is the minimum. Increasing the distance between drainlines will enhance independent functioning of each drainline and the overall function and life of the system. This is not applicable on lots where installation area is limited to initial installation site plus replacement area. Where total lot width “on contour” will allow, consider extending drainlines in opposite directions at the same elevation (the entire area must be approved by the health department in advance).



“CROSSOVERS” MUST BE HAND-DUG !!!
On serial distribution systems, only the soil in its undisturbed condition will act as the “earthen dam” necessary to insure that the upper line fills completely before effluent flows down to the next line. If the original material is removed by mistake, special effort must be made to create this damming effect with compacted clay, or, a bentonite/soil mixture. The bottom of the crossover pipe shall be no lower in elevation than the top of the stone, chamber, or gravelless pipe in the upper line. Do NOT fill around, or over, the crossover pipe prior to final inspection.



Keep drainfields shallow:
Permits need no longer specify “24 inch maximum installation depth”. 24 inches is the STANDARD installation depth! There is virtually never a reason to install at greater than 24” depth. 18 inches would be preferable, where conditions allow. Shallower installation depths will be required on some sites. The building served, and/or the sewer outlet from the building shall be located at an elevation such that the septic system can be shallowly placed in the designated reserve area. If this is not possible, an effluent pump will be required. Please inform the homeowner or buyer: nothing heavier than a lawn mower allowed over the drainfield, and even then, ONLY when soil is firm!



Installation Reserve Areas, original condition:
Reserve areas are to be protected from traffic or other damage at all times! Reserve areas that are approved while in wooded condition shall remain so. In order to protect the topsoil, and the uniformity of the surface soil layer, only small, sapling-size trees, or smaller brush can be removed, and this removal shall be done by hand, not with a dozer or loader bucket. Careful planning during building construction is often necessary on small lots in order to keep block trucks, concrete trucks, truss cranes, roofing material lifts and etc. from compacting soils. This is especially important during wet weather conditions. You must impress this fact on the builder. Lot approvals will be withdrawn if the installation reserve area is rendered unfit through abuse.


Drainfields utilizing chambers shall not be interconnected by piping into, or out of, the top of the chambers.
The pipes should enter and exit the ends of the lines through the endplates, which are designed for such connections. The knockouts at the top of the chambers are designed for the installation of inspection ports, the installation of which we encourage. These inspection ports would allow for future monitoring of ponding levels in the individual lines, giving an indication of the current and future function of the system. A septic tank pumper could also empty the liquid and some accumulated solids from the line through this port, speeding the rehab of the drainfield should it be decided to “rest” the system. (These inspection/pumping ports can also be installed cheaply with riser pipes from “T’s” installed vertically on gravel systems also.) Cap these inspection pipes flush with the ground surface, or in wooded sites leave them elevated above ground for easy location.



Again, all drainfield lines shall closely follow surface contours.
This typically means that drainlines will seldom be straight, nor will the lines be parallel. The distance between the lines will vary, sometimes widely, from end to end and throughout their length. Chamber sections must fit together snugly. Do NOT try to curve chamber installations by leaving small gaps on one side of a joint. Use a section of 4 inch pipe between two end plates to facilitate a curve, or, use the special fitting provided by the particular chamber manufacturer. Some slopes will be too complex for chambers to be used practically. Berkeley County sanitarians will soon be spot-checking level, elevations, and contours with laser equipment.



Distribution Boxes:
Distribution boxes shall be located at an elevation such that the bottom of the box is above the top of the absorption media (gravel, chamber, gravelless pipe, etc.) in the upper drainline. The box should rest on hand-leveled, undisturbed earth; or, on a bed of gravel (minimum four inches deep). The header ditch, containing the solid pipes from the box to the individual drainlines below, shall be constructed such that the bottom of the ditch is always above the top of the absorption media in the adjacent trench.



Drop boxes:
Drop boxes are NOT a substitute for crossovers. When used, drop boxes shall be located so that the outlet pipe to the downslope absorption trench rests on undisturbed earth, to the same height and specifications as a crossover.



Septic tanks:
Inlet and outlet risers are recommended (soon to be required). The outlet “T” is the longer of the two (35 to 40% of liquid depth). Again, install tanks at minimum depth, in order to allow for shallow placement of drainfield. Outlet filters are recommended on all installations, but particularly for LPP systems and others where solids escaping the tank are more critical. If a filter is installed, there must be a riser to the surface over that manhole. The filter is to be serviced ONLY when (after) the tank is pumped.



Property lines:
Septic systems must be installed at least 10 feet from any property line. Have the owner or builder clearly mark the nearest boundary and ensure that the markers remain through final inspection.



Neighboring wells:
It is possible for wells to be drilled less than 100 feet from a “pre-approved”, or permitted, septic reserve area due to oversight or miscommunication between the health department and others involved. Always double-check adjoining lot well locations.



A percolation test will be required for nearly all repairs.
This will usually require a soils observation hole also. Be innovative on repairs: think “alternate”, rather than, “add-on”.



Water softener backwash:
Water softener backwash should be kept out of the septic system. While it is still legal to discharge into the septic tank, it is discouraged. Pipe this material onto the ground surface, or into a very shallow (less than 3’ deep) pit, away from any sensitive area.



Soil Observation holes:
Dig soil observation holes “on contour”, except in limestone soils. Excavations in limestone soils shall be dug in an “east-west” orientation so as to best explore for bedrock. *All excavations in limestone soils shall be backfilled with the rear bucket, compacting soil with this bucket at a maximum of 12” lifts. This backfill should be performed as soon as possible after the site evaluation is completed. Remove large rocks from backfill material.



All Berkeley County installers are required to attend the annual installer training. If you miss the meeting, you must view the recorded version at the health department offices.



Please advise homeowners on septic tank use and maintenance:
No grease to be poured down drain (kitchen grease is garbage, not sewage). Try to spread laundry through the week. Have tank checked for solids accumulation (at an interval dictated by number of people in household; call for recommendations). Nothing but wash water or bathroom waste should go down the drains. If an effluent filter is installed, clean ONLY when the tank is pumped.