Where Is My Tank

The question is, where is your tank(s) and how deep below grade are the access lids?  To locate your tank:

1. Get a copy of the as-built drawing from the health department. It should show the size and location of your septic tank(s) and leach field.  See Creates a Septic File under Owner's Manual to learn about as-built drawings.
2. Measure off the triangulation distances given on the as-built drawing, usually to the center of the inlet chamber lid.
3. Probe or dig for the lids.  This can be quite difficult if the ground is hard and dry; you may want to pre-soak the ground with a soaker hose for several hours before you start digging.  In most cases, the tank or access lids are within 2’ of the surface
4. Dig a 30” diameter hole down to the inlet chamber lid.  If your tank is a single chamber tank, it can be properly cleaned through the inlet access lid; but if you have a two chamber tank, you will need to also find the outlet access lid and dig it up.
5. Open the lid and look for the end wall where the 4” sewer pipe comes into the tank from the house.
6. Measure off for your tank size, the following distance perpendicular to the entrance end wall of the tank to the center of the outlet chamber lid: 1000 gallon tank = 5.5’-6’; 1250 = 7’; 1500 = 8.5’-9’.
7. Dig up the outlet chamber access lid.
8. If you are extraordinarily lucky, the as-built drawing is accurate and you have hit the lids spot on.  If not, keep digging until you find them and correct your drawing.
9. If your lids are deeper than 8” below grade, you should put risers on to bring the access up to the surface, or at least to 8”.  See Makes Tank Lids Accessible under Owner's Manual.
10. Put your as-built drawing, properly revised in your septic file.

If you can’t find the tank, either because the drawing is inaccurate or it is deeper than 24”, then you will need to have it located.  Please see Locating Services under Resources.

Indoor and Outdoor Odors

Some people experience sewer gas odors, either inside or outside a house served by a septic system.  Your tank produces several gases: some odorless, like methane; and others highly noticeable, such as hydrogen sulfide. 

Odors Inside the House:  These odors are usually caused by a trap not being sealed.  Every fixture in the house - including floor drains, tub drains, sink drains and shower stall drains - has a P-trap beneath it which is sealed with water and prevents gases produced in the septic tank from entering the house. If a fixture remains unused over several months, the water in the trap can evaporate, allowing gas to enter the house.  Therefore the most probable culprit of an indoor odor is an under-utilized fixture, such as a floor drain in a basement or utility room ­-or tubs, sinks and showers in an infrequently used extra bathroom.  Drying out of a P-trap occurs more frequently in the winter when the air is dry, and also after a very windy period.  The simple fix is to pour about one quart of water in each drain to re-seal it.

Odors outside the house:  These odors are usually caused by those same tank gases venting through the roof vents of your plumbing system. On a day with a slight breeze, the gas can be pulled down to a deck or patio area, or into an open window, by the vacuum created on the lee side of the house.  This problem can be solved by extending the offending vent pipes above the roof line, or installing one-way check valves - permitting air to enter but not to escape the vent.

Back-Ups and Slow Draining

If you suddenly have a back-up or slow draining problem, and before you call us, you can open the inlet lid and look inside to see if the water level is normal, or if there is an obstruction at the inlet pipe.  If the inlet pipe is clear, you may have an obstruction in the line and will want to call a rooter service to clear it.  Most rooter services will charge you for a visit, and then tell you they will not run the snake until the septic tank is pumped. In fact they can clear the line without pumping.  Please see Rooter Services under Resources. 

If there is a large mat or obstruction at the inlet, you may be able to clear it yourself with a stick or shovel.  This may mean you should call us to pump the tank. If you have an engineered system with a pump and alarm system, and your alarm sounds, you should first look in the pump chamber to see what is wrong, or check the 2^nd chamber of the first tank to see if you have an effluent filter that is plugging.

A back-up through the sewer line into the house may also indicate a clogged or saturated/waterlogged leach field.  If this is the case, you may also experience sewage either surfacing above your tank or the ground over your leach field.  If this happens, the system becomes an annoyance and hazard to your and your neighbor's health, and a new field will have to be installed.  Please see System Repair under Services.

Signs of Leach Field Failure

When a leach field fails, it is no longer able to disperse the effluent from the tank at a rate equal to the flow from the house.  To determine whether a system is in failure and needs repair, we look for the following:

• No cast iron pipe at the tank outlet:  when the outlet pipe has broken off, effluent is unable to be carried to the field.

• An “overfull” tank: the tank is always full, with the effluent level resting just below the outlet tee.  If the effluent level rises above the outlet tee and remains there, it indicates that effluent is not being properly distributed to the field.

• Surfacing effluent in the field:  when effluent surfaces above the field, it indicates that the field has become saturated or “water-logged.”

• Rich growth and/or thistles on top of the leach field

• Considerable flow-back:  after the tank has been pumped down, the flow-back into the tank can be observed.  If the flow-back is considerable ­­­­(more than the amount in the outfall pipe) it indicates that effluent from the field is flowing back into the tank instead of percolating into the soil.

• Excavate and open the distribution box: the distribution box can be excavated and opened to verify effluent is reaching the field.

Please see System Repair under Services.

How to Keep Your Leach Field in Good Condition

Maintaining a regular tank cleaning and system inspection schedule is the most important factor in keeping your leach field in good condition.  If any solids from a dirty tank reach the leach field, it can cause it to fail.  Likewise, regular inspections can detect problems within the system before costly replacement is necessary.  Please see Tank Cleaning and Inspection under Services.

Seed the area of your field with a low-growing grass and keep the grass and weeds mowed to a height of 10".  If you mow the grass too short, then the grass will not help take moisture upwards.  If you allow the weeds to grow too tall and numerous, they will shade the ground and prevent evaporation through the warmed soil.  During the winter, the grass and roots provide a wicking action for upward movement of water.

Leach fields may be shallow - covered by perhaps 12"-18" of soil and the soil may be damp.  It is important that the soil stay as porous as possible to allow air into the bed.  For this reason, it is critical that the area not be compacted.  So, keep all vehicles, buildings, sheds, corrals for livestock, fences and trenches off the field.

If you have alternate (two or more) leach fields, an aerobic (Nutt Shell) system or a low pressure drip irrigation ("Bell-Pat") type field, these systems have a diverter valve, zone valves or a surge tank with risers and a plug, all of which require periodic switching of field usage in order to rest one field or zone.  Contact us for instructions on periodic valve changes for resting zones of your field, if you are not certain of the requirements and method.  Also see About Valve Switching under Troubleshooting.

Disposing of Grease and Oil

The addition of excess grease or oil from food preparation processes is not helpful to your septic system.  When you wash or rinse cooking oils or grease in hot water at the sink, it starts to congeal on its way down the sewer line to the septic tank, and can form a hard, caked clog at the inlet tee or baffle in the tank.  This can restrict the flow into the tank and result in a blockage and backup into the house. The grease can be put into suspension again when a hot load of laundry water and detergent enter the tank, and the grease will travel through the tank and congeal again.

The problem is compounded if you have any filters in your system – either at the outlet of the 1st tank or a screened vault or Biotube filter at the lift station pump.  These filters screen solids 1/8” and larger, and grease or oil in suspension adheres to the screen surface, reducing the screen size and resulting in premature plugging.

The secret with grease and oils is to keep a 1 lb. coffee can in your refrigerator, and pour all cooking grease and oil into the can after cooking and before washing.  The contents of the can will not produce an odor while refrigerated.  Once the can is full, put the plastic lid on and throw the can away in the trash.

Preventing Excess Water

A septic system is designed to handle a limited amount of water in a 24 hour period, and a system will perform properly and last longer if water conservation is practiced, as well as the hydraulic load being spread out evenly throughout the week.  This means spreading large water usages, such as laundry loads and bathing, throughout the week.  Example:  Don’t do 6 loads of wash on a Saturday.  Please see Guards Against Too Much Water under Owner's Manual.

There are 3 sources of excess water that are hard to detect, so they need to be investigated carefully:

1.  Leaking toilets: Put 1 food coloring/leak detector tablet in each toilet tank (open the lid on the tank).  Wait 5 minutes and see if any blue/green color enters the toilet bowl.  If color enters, you may have a leaky flapper valve or a malfunctioning shut-off float valve or water is overflowing the 1” diameter overflow pipe.  Check the water line in the tank to see if there is an overflow problem.  If so, re-adjust the float bowl arm by bending it down so the shut-off float valve will shut off the water before it reaches the top of the overflow pipe.  If the water level is okay, then your flapper valve is leaking.  Most septic systems are designed for a flow of 450-600 gallons per day.  A badly malfunctioning toilet valve can send 1,000 gallons into the leach field in one day! causing the field to saturate and the infiltration rate to slow dramatically.  To save your leach field from becoming saturated, replace your flapper valve.  They cost $4-$5 and are obtainable from a hardware store or building center.  The harm caused should not be permanent and the field should recover once the leak is stopped.

2.  Malfunctioning water softeners:  These devices go through a back flush cycle every 1-3 days, during which salt brine is back flushed through the bead medium in the softener tank, carrying away the iron or other minerals that make the water hard.  The brine is drained into the septic tank.  Often, this back flush cycle will stick in the ON mode and not shut off properly. Usually, you can run a back flush cycle manually, overriding the automatic cycle.  Do this and watch to be sure the cycle lasts only as long as it is set for, and does not continue forever.  If it is malfunctioning, have the unit serviced by your softener company.

3.  Basement ground water sumps:  These are the round black plastic basins in the basement floor with an electric pump inside and a drain line.  They are installed to prevent wet basements and are fed by a French drain system installed in the perimeter of your foundation wall/footing.  The flow from these basins is supposed to be pumped outdoors to a separate dry well or to a surface or storm drain, and NOT into the septic system.  Check to be sure your sump pump is not discharging into the septic tank. If you trace the drain pipe from the pump and it branches into the 3” sewer main, then it is going into the septic system.  A proper installation will have the pump drain line exiting the house by itself.

About Valve Switching

Low pressure pipe systems are also known as “Bell-Patt” or low pressure drip systems.  They consist of one or more fields, divided into sections usually numbering from 4 to 10.  The effluent is demand dosed into the field from the pump chamber, usually in 150 – 250 gallon doses, once or twice a day.  The flow of effluent into each section is controlled by a 2” ball valve, attached to a manifold with all the other field valves.  The valves and manifold are housed inside one or more large green plastic sprinkler control boxes, or a wooden box made by the system installer.  The valve box(es) are located at the head of the field on the upslope corner, at the opposite end from the observation ports, which look like a series of white soldiers spaced 8’-12’ apart.

When we install these systems, we mark the field section number, compass direction and up or down slope of each valve with indelible marking. The #1 valve controls the uphill section closest to the valve box(es), and the last numbered valve is furthest away from the field and controls the lowest down slope section.  For example, in the illustration, if the field is to the left and down slope from the valve boxes, the #1 valve is to the left, controlling the upper and the #6 valve is the closed one to the far right and controls the lowest section in the field.

The system is designed oversize by one section so that you can rest one section at a time.  If you have 5 sections, 4 will be on and 1 will be off.  The section should stay off for 6 months allowing it to dry.  Than, you turn that one ON and the next one OFF, so rotating in sequence --- forever.  This prolongs the life of your field.  Field section rotation is one of the services we provide under our Maintenance Program for Engineered Systems. 

Grass Seeding After Installation

It is important to re-seed with grass those areas that have been disturbed by the excavation process during the installation of your septic system.  A healthy stand of grass will prevent erosion and the infestation of weeds, and the deep-rooted dry land or prairie grass mixtures help your disposal or leach field operate by aiding the evapotranspiration process, which removes 20%-30% of the water in a traditional 3’ deep absorption bed or trench system and 70%-90% in shallow low pressure pipe or drip irrigation systems.

There are myriad varieties of grasses that are suitable, including the prairie or dry land pasture mixes, tall fescues, blue grama, crested wheatgrass and brome.  Most mixes cost about $5/lb and you will need between 3-8 lbs./1,000 SF of area to be covered, depending on the variety.  The seed can be purchased at most rural feed and tack stores, or from Rocky Mountain Seed in downtown Denver.  The seed is best planted between mid-March and mid-September. The seed will need watering to get established, so Spring is probably the best season to take advantage of rains or snows.

You can broadcast the seed by hand, or use a small, inexpensive hand spreader.  After broadcasting, scratch the seed in with hand rakes or a drag cultivator.

Once established, you can leave the grass at its natural height, or mow to 3”.