If you do not find an answer to your question please call us at the numbers listed below.

My alarm is going off or, there is a problem with my septic system.
Whalen Designs does not offer service calls however, we recommend these reliable companies:

A Wesco Septic:

Tri-County Septic:
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Is my septic system starting to fail?
These are some commons signs of system failure:

Bad odors around the drainfield area especially after
heavy water use or rainfall
Very wet spots with lush green grass growth over the
drainfield or septic tank areas
Standing water in the drainfield area
Plumbing or septic tank back-ups
Slow draining fixtures
Gurgling sounds in the plumbing system

If your septic system is failing Contact Us and we can help you diagnose the problem.
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When does my septic tank need pumping?
It is recommended to pump your septic tank every 3 - 5 years. How often you pump depends on the amount of water you use.

General rule of thumb: the more people using your septic system = increased water flow = your septic tank will fill up faster = more frequent pumping

The septic tank should be pumped whenever: the bottom of the scum layer is within 3 inches of the bottom of the outlet baffle or the top of the sludge layer is within 12 inches of the bottom of the outlet fitting. It may be possible that the septic tank will need pumping more often than 3 - 5 years. The only sure way to know is to have the septic tank inspected annually.
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How do I maintain my septic system?
King County:
Contact a certified On-Site System Maintainer (OSM) to inspect and monitor your system on a regular basis. A certified OSM has two or more years of experience, has completed a monitoring and maintenance class and has passed an exam given by Public Health – Seattle & King County.

To find an OSM visit the King County website

Snohomish County:
You may contack a licensed designer, installer or pumping company to do the maintenance. The frequency of inspections depends on the type of your septic system.

Gravity systems:
It is the owner's responsibility to inspect their systems either themselves or by a certified Pumper or On-Site System Maintainer:
- Annually with a garbage disposal
- Every three years without a garbage disposal

Pressure Distribution systems:
- Check Annually
- If your system includes an Aerobic Treatment Unit (ATU), the ATU should also be inspected
Every 6 months.

Mound, Sand Filter, Upflow Sand Filter or Sand Filter to Mound systems:
- Every 6 months (Glendon BioFilter only)
- Annually if your system includes an Aerobic Treatment Unit (ATU), the ATU should also be inspected
Every 6 months.
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What kind of septic system do I have?
Gravity Drainfield
As the name implies gravity drainfields work by letting gravity drain the effleunt. This means that a gravity drainfield area must be below the draining level of the septic tank. If this is not the case then a pump tank is necessary and it is called a pump to gravity system.

The soil below the drainlines filters effluent as it passes through the pore spaces. Chemical and biological processes treat the effluent as it percolates down through the soil. The treatment process cleans the effluent before it reaches the groundwater.

Pressure Distribution Drainfield

Pressure distribution systems are usually installed when there is less than optimal soil depth available for complete treatment of the effluent by a gravity system. Pressure distribution systems always have a pump and therefore they dose the drainfield with effluent and then let it rest until the pump tank accumulates enough effluent from the household for another dose. In addition a series of pressurized lines from the pump tank to the drainfield make sure the entire drainfield receives effluent at the same time.

Sand Filter System
When there is minimal soil available for treatment, a sand filter system is sometimes used. This consists of a sand containment vessel between the pump tank and the pressurized drainfield. The sand acts to treat the effluent before it enters the shallow soils on site. This effectively makes up for the lack of soil depth. The sand filter itself is a concrete or PVC-lined box filled with a specific sand material. A network of pressurized lines is placed in a gravel-filled bed on top of the sand. The septic tank effluent is pumped through the pipes in controlled doses to insure uniform distribution. As the effluent trickles down through the sand it is treated. A gravel underdrain collects and moves the treated wastewater to either a second pump chamber for discharge into a pressurized drainfield or the filter can sometimes drain into a gravity flow drainfield.

Mound System
Another system that can be used when a site has inadequate soil depth is a mound. A mound is a drainfield raised above the natural soil surface with a specific sand fill material. Within the sand fill is a gravel bed with a network of pressurized pipes. Septic tank effluent is pumped through the pipes in controlled doses to insure uniform distribution throughout the bed. Treatment of the effluent occurs as it moves through the sand and into the natural soil.

For a more complete description of each system type, including pictures and system variations, please visit the King County website
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What are the do’s and don’ts of a septic system?

Regularly inspect and maintain your septic system
Routine maintenance can lengthen the life of your septic system.

Pump your septic tank every 3-5 years

Be conscious of your water usage
Using less water may increase the life of your septic system.
Repair all leaky fixtures quickly.
Use "low flow" fixtures on faucets and shower heads.
Spread laundry washing throughout the week and wash full loads.
Dishwashers and washing machines should not be run at the same time.
Direct water from land and roof drains away from the drain field.

Landscape carefully
Grass is the best cover for your septic tank and drainfield. Other plants with very shallow root systems can also be used for landscaping. See landscaping question below for a more detailed list of acceptable plants.

Keep tank lids accessible
Have "risers" installed to make septic tank pumping and monitoring visits easier and less time-consuming.

Contact a certified professional to repair your system
Prevent costly future system problems by contacting a certified professional, such as an Installer, Designer, or qualified professional Engineer to repair your system. Make sure they obtain the proper Health District permits.


Don't use a garbage disposal
Garbage disposals add solids and grease which can clog or choke your drainfield. If you absolutely must use one, limit your use as much as possible.

Don't flush anything except toilet paper into your septic system
This includes diapers, cigarette butts, coffee grounds, sanitary napkins, tampons, condoms, grease, oils, unwanted medications or paper products other than toilet paper. Products labeled as "flushable" may not be suitable for an on-site sewage system.

Don't put household chemicals down the drain
This includes chemicals such as paint products, drain and floor cleaners, motor oil, antifreeze, and pesticides. These chemicals destroy necessary bacteria in your system that break down solids.

Don't park cars and trucks on your drainfield or septic tank
In addition, keep patios, carports, decks, storage sheds, sports courts, landscaping plastic, and grazing animals off the drainfield and drainfield reserve areas. This will prevent soils from being packed down and pipes from breaking.

Don't use septic tank additives
These products may add extra solids to the system that can clog your drainfield. The chemicals can also pollute ground and surface water. If you must use additives, use only those that have received written approval from the Washington State Department of Health. It is unlawful to use any non-approved additive.

Don't drain water from hot tubs into your septic system
Large volumes of water can 'drown' your drainfield and chlorine can destroy important bacteria.
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How does my septic system work?
A septic system is comprised of two main parts. These parts are the septic tank and the drain field.

A septic tank is usually a large buried rectangular or cylindrical container made of concrete, fiberglass or polyethylene. Wastewater from all plumbing fixtures drains into this tank. Heavy solids sink to the bottom where they settle and bacteria produces digested sludge and gases. Lighter solids that float such as grease, oils and fats, rise to the top and form a scum layer.

Systems constructed before 1975 usually have single compartment tanks. Those built from 1975 and on are usually two compartment tanks. This is important to know when having the septic tank serviced, as both compartments of a two-compartment tank need to be pumped.

Wastewater leaving the septic tank is a liquid called effluent. While it has received some treatment in the septic tank it is still unpleasant smelling and contains disease organisms, organic wastes and other pollutants. This effluent requires proper treatment and disposal otherwise there can be significant environmental and public health problems.

The drainfield is where liquid from the septic tank flows through pipes in your yard for final treatment by organisms in the soil. Grass and/or shallow-rooted plants are the best covers for your drainfield.
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How do I get a copy of my As-built?
For Snohomish County please visit:

For King County please visit:
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What kind of landscaping can I do with a septic system?
Your landscape design should not interfere with the natural functioning of your septic system.

First you must know where your septic tank, drain field and reserve area are located. Use your As-built drawings (septic system map) to determine the location of this areas.

For information on ordering your As-built drawings please visit the “How do I get a copy of my As-built?" question above.

Once you have found these areas, avoid landscaping on or near the septic tank.

The septic tank, drainfield and reserve area should be clear of:
- underground sprinkler lines
- decks, patios, sports courts, or utility storage sheds
- swingsets
- sand boxes
- paved or dirt driveways
- parked vehicles

Suggested plant list: (by the Washington Sea Grant Program)

- Don't plant a vegetable garden on or near the drainfield or reserve area
- Plants over the septic system may be disturbed or destroyed with repair work
- Don't put plastic sheets, bark, gravel or other fill over the drainfield or reserve area
- Don't reshape or fill the ground surface over the drainfield and reserve area (just adding topsoil is generally OK as long as it doesn't exceed a couple of inches over the drainfield area)
- Grass or the existing native vegetation are the best covers for your drainfield and reserve area
- Direct all surface drainage areas away from the septic system
- Use shallow-rooted plants (see Plant List below)
- Avoid water-loving plants and trees
- Do not make ponds on or near the septic system and the reserve area

- Fescue
- Lawn
- Ornamental grasses
- Wildflower meadow mixes

Groundcovers for sun:
- Bugleweed (Ajuga)
- Carpet heathers (Calluga)
- Cotoneaster (Cotoneaster)
- Ground Ivy (Glechonma)
- Kinnickinick (Arctostapylos)
- Periwinkle (Vinca)
- Soapwort (Saponaria)

Groundcovers for shade:
- Bunchberry (Cornus)
- Chameleon (Houtuynnia)
- Ferns
- Mosses
-Sweet Woodruff (Galium)
-Wild Ginder (Asarum)
-Wintergreen (Gaultheria)
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What do I do if my power goes out?
Be water wise. Your pump system is dependent on electricity to move the liquid sewage from the septic tank to the drain field. As you continue to use water (flushing toilets, doing dishes, taking showers, etc . . .) the septic tank fills but does not get pumped. To avoid filling the pump tank and possibly causing sewage to back up into your house reduce your water usage while the power is out. Cut your shower time down, don’t do laundry, and don’t flush the toilet every time it is used for only liquid waste.

If your septic system has a pump, what you do next depends if the pump is “on demand? or if it has a "timer."

On-demand pump system:
An on-demand pump system is the most common kind of pump system. The on demand pump begins its pump cycle whenever the wastewater volume reaches a premarked level in the septic tank, and the effluent (liquid sewage from the septic tank) is pumped into the drainfield.

When there is a power outage, the effluent is not being pumped into the drainfield. The septic and pump tank will collect the wastewater throughout the power outage, and release it all at once when the power is restored and the pump starts working. Too much water pumped into the drainfield will flood the drainfield and cause complications. What can you do? Follow these 3 steps and become a human timer:

-Turn the circuit to the pump 'off' while the power is out.
-When the power is restored, turn the pump 'on' for 2 minutes and 'off' for 4 – 6 hours. You are now "dosing" the right amount of effluent into the drainfield over a given period of time. If there was little water use during the power outage, the pump may automatically turn off during the first manual dosing.
-Conserve water and continue the 2-minute pumping every 4 – 6 hours until the pump turns itself off.

A pump system with a timer controls the number of times the pump starts and stops. It manages how much effluent (liquid sewage from the septic tank) goes into the drainfield in a 24-hour time period. Timers make sure that the drainfield only gets as much effluent as it was designed to handle. The timer system will eventually take care of itself once the power is restored. If your system has a timer, it may be indicated on the as-built (scaled drawing of the septic system). It is usually found on a wall or post near the pump tank or in the garage.
What can you do? If the power has been off for awhile, the timer will be behind. In order to let your timer catch up, continue to conserve water for an additional day or more.

if the high water alarm sounds when the power is restored, the effluent has backed up into the reserve storage area of the pump tank. Refer to Steps 1-3 under the on-demand heading to start pumping the backed up sewage to the drainfield.
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