SEPTIC SYSTEM PRACTICES
The efficiency of a septic tank for separating solids from the clarified liquid effluent is
directly related to the length of time the water is in the septic tank, which in turn depends
on the household generation of sewage. The more water used, the faster if passes
through the system. Conversely, the less water used, the slower it goes through the septic
tank and the longer the solids have to settle out so that they are not passed on to the
In recognition of the required septic tank retention time and the size of your leachfield(s),
the District has assigned a Discharge Limit for each system.
Remember that all water that goes into the septic tank must eventually be absorbed by the
soil. The less water entering the system, the less there will be for the soil to absorb.
Not only is the total amount entering the septic tank critical to proper operation, but the
rate at which this water enters is extremely important. For example, doing one load of
laundry per day for five consecutive days is easier on the system than doing five loads on
one day. Best practice is to spread water usage throughout the day and throughout the
week rather than to have dramatic daily peaks. This is important both hydraulically and
because the temperature of the wastewater in the tank can be raised by a sudden dramatic
inflow of hot water and this can cause solids to be mixed and carried out with the effluent.
In recognition of the important of spreading use out through the day, the new systems are
incorporating timed dosing of sand filter to minimize peak loading by dosing throughout the
day and allowing storage volume in the tank for daily peaks.
To reduce your water usage:
- use water saving devices
- repair leaky faucets and plumbing fixtures
- replace toilets with models that use 1.6 gallons per flush or less
- take shorter showers
- use only a partially filled bathtub
- run clothes washer and dishwasher when they contain a full load
- don't let water run while brushing teeth, washing dishes, etc.
- don't drain spas or hot tubs into your septic system
Just as important as how much water goes into your system is what goes into your system.
Remember that all phases of onsite wastewater treatment rely on a mix of biological
organisms to clean and purify the wastewater -- a community of bugs is working for you,
so do not dispose of products that will kill off these hard working bugs.
As a general rule, only three things should go into the septic tank: human wastes, toilet
paper and waste from toilets, bathing fixtures and kitchen sinks. A good rule is: don't use
your septic system for anything that can be disposed of some other way. The less material
you put into your septic tank, the less often it will need pumping.
- Avoid using a garbage disposal unit. Compost scraps or throw them out with the
- Collect grease in a container near the sink rather than pouring grease down the
- Minimize the disposal of paper products. Non-degradable items such as disposable
diapers, sanitary napkins or tampons, Kleenex, cigarettes and paper towels are
especially harmful. Use a toilet paper that will dissolve quickly upon disposal. To
test, place a sheet in a mason jar of water and check in one hour. It should have
completely disintegrated after one hour of standing. Anecdotal evidence from
pumpers indicates that paper with dye and texture affects the ability of the product
to break down and cause a deterioration of the quality of the effluent. Look for
brands approved by the National Sanitation Foundation (NSF).
- Minimize the amount of sand entering the system by removing excess sand prior
to showering, and by shaking excess sand from clothing prior to laundering.
When used in normal quantities and as recommended by the manufacturer, household
cleaning products should not have any harmful effects on your system. Excessive
quantities of strong bleaches, detergents and drain cleaners will eventually kill off the
essential bacteria in your tank. Moderation should be the rule.
Do not use toilet bowl cleaning tablets. These are generally chlorine based and can
significantly increase the concentration of chlorine in the wastewater discharged to the
septic tank which in turn, could adversely affect the biological communities present in the
Do not dispose water softener backwash into your septic system. The backwash brine
contains a high level of chlorides that can destroy the bacterial population and inhibit
biological digestion that is essential to a properly functioning tank. The brine can also
interfere with sedimentation and can increase the hydraulic flow through the tank.
The disposal of toxic chemicals into your septic system is unlawful and detrimental to your
septic system (remember those hard working bugs), the environment and to District
personnel and/or septic service personnel.
Toxic chemicals that should not be disposed of into the septic system include but are not
limited to the following:
- gasoline or other fuel products
- motor oil
- brake fluid
- radiator cleaners
- caustic chemicals
- paint thinners or strippers
- wood preservatives
- photographic chemicals
- electroplating solutions
- fiberglass resins
Please contact the District for advice prior to the disposal of chemicals from a hobby or
While many products on the market claim to help septic systems work better, the truth is
there is no magic potion to cure an ailing system. Some proprietary products that claim
to "clean" septic tanks contain chemicals that may cause the scum and sludge to be
discharged from the tank to the leachfield. In essence they change a simple maintenance
item (regular pumping of the tank) into a major system failure (clogged leachfield).
There are two types of septic system additives: biological (bacteria, enzymes and yeast)
and chemical. At best an additive is benign; it provides no benefit and it costs you some
money. At worst it can damage concrete or wood tanks and clog the soil; and products
that contain solvents can contaminate the groundwater. The general consensus among
septic system experts is that septic system additives are unnecessary, possibly harmful,
and should not be used. The naturally occurring bacterial population in your tank do not
need to be augmented for proper operation of your system. The best results come from
a balanced and well-maintained system that is not overloaded or abused.
Unless specifically designed for vehicle loading, no portion of your onsite wastewater
disposal system should be driven on. If your tank is in an area subject to traffic, install a
barricade to prevent damage to the tank and/or risers.
Traffic is generally prohibited from leachfields to prevent compaction of the soil and to
minimize the breaking and collapsing of leachfield pipes. Soil compaction can severely
limit the transfer of oxygen and therefore hasten the development of anaerobic conditions.
Similarly, leachfields should not be paved or cemented over. Decking is generally
acceptable, however, access must be provided for District inspections and maintenance
work. The supporting structure of the deck must be reviewed by District staff to ensure
that the construction is consistent with District code and will not interfere with the
wastewater disposal system.
If you rent your property, please make your tenants aware that your property is served by
an onsite wastewater disposal system, and that there are restrictions regarding the amount
and quality of wastewater discharged. Please post the "Do's & Don'ts"
list in the kitchen and/or bathrooms. Please include the phone number of the contractor who
maintains your system so that an alarm or pump failure can be addressed. Also, please
include the Daily Average and Daily Maximum Discharge Limit so your tenants can modify
their use accordingly. The District can install flow restrictors to assist you in ensuring that
your tenants do not abuse your onsite system.