Logo, American On Site - Septic Systems
(503) 829-7600
31881 S Highway 213
Molalla, OR 97038

Dependable Septic Systems

Who We Are

Turn to American On Site in Molalla, Oregon, for the best solutions to all of your septic needs. We are a full-service company specializing in septic systems.

From installations to pumping and repair services, our professionals have been trained and certified to install the latest technology in aerobic systems.

Learn More about American On Site

For Your Peace of Mind





American On Site has been in business since 2003.

Septic Services

We Offer the Full Range of Septic Services

  • Septic System Quality Performance Testing
  • Septic System Locating and Inspections
  • Oregon DEQ Verification Inspections for Home Sellers and Buyers
  • Septic System Repair, Replacement and New Installations
  • Custom Design and Installation of Greywater Bypass Systems
  • Emergency Septic System Services
  • Routine Septic System Maintenance

Is Your Septic System in Trouble?

Warning Signs of Septic System Failure

How do you know if your septic system needs attention? Here are some of the most obvious things that any Oregon home or business owner with a septic system can easily identify:

Inside Warning Signs:

  • Bathtub and/or Sink Drains. If your drains are slow, sluggish, gurgle or tend to back-up often, you may be facing a serious septic system issue. Whether the back-up is gray water or sewage sludge, this is a clear warning sign that should never be ignored. Contact American On Site immediately to schedule an emergency appointment. We can identify whether or not you have a simple-to-fix block in the sewer system or are facing a more serious repair or replacement issue. Better yet, we can take care of the problem for you on the spot. Often, drain problems are easily fixed and calling us for a septic system consultation can save you stress and money now, by preventing major damage in the future from neglect.
  • Foul Odors.  If you notice an ongoing foul smell inside your home or business, especially in the kitchen or bathroom areas, this would constitute a septic system emergency. The bad smell is awful enough, but the risks to you and your family's health make getting immediate professional help a priority.

    The smell may be truly foul, musty or a combination of both. As soon as you notice the odor,  call American On Site for emergency septic system service. And be sure to alert us to this issue so that we can get your on our emergency service schedule, which takes priority over our regular service schedule. Although it is possible that the foul odor you are smelling may come from a different source, American On Site can determine whether or not your septic system is the cause. If it is, we will work quickly to repair or replace the part/s of your septic system that needs attention (usually its the drainfield or septic tank). By the time we are done, the foul odor will be gone.

    Better yet, before our crew leaves, you will know when your next septic service will be. You can rest easy after scheduling your regular septic service appointment/s in advance. American On Site will send you service reminders via email or post card...or both, depending upon your preference.

Outside Warning Signs:

  • Pools, Puddles and Soggy Spots. If you notice areas of standing water near your septic system, especially in the drainfield or above where the septic tank is buried, you may need emergency septic system service. Pay close attention to these areas, especially when draining your bathtub or doing laundry. If the excess water being drained produces spots where water collects in pools, puddles or soggy spots, it is time to call American On Site for emergency septic system service.

    For Oregonians, our rainy season can be another opportunity to identify problems with your septic system. Look for excess standing water over the surface of the drainfield or septic tank areas during or just after it rains.
  • Foul Odors.  If you notice a foul smell outside of your Oregon home or business, especially near your septic system, it is time to call American On Site for emergency septic system service. Whether or not there are any obvious physical signs (see Darkened or Black Spots and Pools, Puddles or Soggy Spots), the presence of a disturbing smell should always be a high priority to investigate. If the foul odor is caused by a septic tank overflow, American On Site may be able to fix the problem simply by pumping the tank or repairing the drainfield. In more serious cases, you may have a worn out drainfield or septic tank. Let us do the worrying and the fixing. All you need to do is call American On Site and we will do the rest.
  • Darkened or Black Spots. If you notice dark, discoloration near your septic tank, there is a high likelihood that you have serious issues with your drain field and/or your septic tank. It may be that you have waited too long to get your septic tank pumped and the spots are a result of unprocessed overflow. Or it may be that your septic system has simply worn out and needs to be repaired or replaced.  Whatever the cause, these dark spots in the drainfield represent raw sewage and are a health hazard, so call American On Site for emergency septic system service.

We hope that this list of common warning signs for septic system failure helps you in being alert to potential issues. Still, we highly recommend that you schedule regular septic system service appointments with us to ensure your system is fully operational and that the septic tank sludge is removed in a timely manner.

Trust American On Site to take care of your septic system and we will be there when you need us.



Proudly Serving the Northern Willamette Valley


Multnomah County,Oregon;


Clackamas County,Oregon;


Washington County,Oregon;












Lake Oswego,Oregon;








Mt. Angel,Oregon;




Oregon City,Oregon;








St. Paul,Oregon;




West Linn,Oregon;






and Surrounding Communities


Trust American On Site to take care of your septic system and we will be there when you need us. Give us a call to schedule an appointment, then just relax and let us do the work for you!


What NOT to Put in Your Septic System & WHY!


Septic- Worker


Septic- Working


Septic- Construction

How Do Septic Systems Work?

If your Oregon home or business is located outside of municipal sewer system boundaries, you likely have a septic sewer system. A septic system is an underground wastewater treatment system that is “self-contained” (a complete system that functions on its own). You probably know all of that, but have you ever wondered how a septic system actually works?

Terms, Components and Functions of a Septic System:

  • Plumbing VentVertical exhaust pipe with a vent in bathrooms that enables sewage fumes to exit the building.
  • Wastewater – The used water and sewage that is flushed down the toilet, flowing from the building through the sewage pipes into the septic tank.
  • Septic Tank – A water-tight tank or container – usually made of fiberglass, but may be made of metal or concrete – functions as a holding tank for the wastewater. The purpose of containing the wastewater for a period of time is to allow separation into three layers referred to as sludge (bottom), scum (top) and effluent (middle).
  • SludgeThe solids that accumulate on the bottom of the septic tank, including feces and other materials that have been dumped down the drains or flushed down the toilets. The sludge separates naturally because it is heavier than water.
  • Scum – The layer of solids that float to the top of the wastewater, including laundry lint, oil, soap film, grease, food chunks, garbage and oils. The scum separates and rises to the top because it is lighter than water.

NOTE: Both the scum layer on top and the sludge layer on the bottom are held by the tank. Bacteria and enzymes break them down, enabling some of these layers to become part of the effluent water that is released into the drainfield. However, inevitably, some of the scum and sludge is not able to be broken down. This is the material that is removed by American On Site through regularly scheduled septic tank pumping, followed by cleaning.

  • Effluent – This is the central layer of wastewater in the septic tank. It is also the largest layer in the tank and what gets released into the drainfield.
  • Distribution Box – From the septic tank, the processed wastewater flows into a distribution box, then it travels on by way of a non-perforated pipe and feeds into the leach lines.
  • Leach Lines – There are several leach lines embedded anywhere from 12 to 36 inches deep into the drainfield. The purpose of the leach lines is to spread the effluent across the drainfield as it is released.
  • Drainfield (alternately referred to as a leachfield) - The drainfield is designed to finish the job of cleaning the greywater naturally and releasing it back into the natural aquifer deep underground.

The drainfield works with the help of nature by allowing the effluent water to pass through the drain media on its way to the trench bottom where the microbes that are naturally available within the soil are able to process the bacteria, viruses and organic substances remaining within the effluent water. In this way, the drain field traps and breaks down organic matter and harmful pathogens, while allowing the now-purified water to continue on its way down into nature's aquifer.

  • “Water in, water out” – A common  phrase used in the septic system industry, which refers to the fact that the amount of water or sewage that goes into the septic system is equal to the amount processed through the septic tank and ultimately the same amount that flows out into the drainfield. (one gallon in equals one gallon out into the drainfield). This concept is fundamental to septic system operation. What this means to you is that the more people who live in your home or work in your building, the more heavily your septic system is being used and the more frequently you need to schedule your regular septic tank to be pumped out.

A similar concept is that whatever is flushed down the toilet or allowed down the bathtub or sink drains will end up in the septic system. For those inexperienced with septic systems, putting the wrong things down the drains or in the toilets can create some serious problems. See What NOT to Put in Your Septic System and WHY!

Having a septic system is a good thing. These systems cost less to operate than municipal systems and – because they are relatively small, self-contained systems – they do not need nearly the extensive pipe lines, pump sizes or drainfields that municipal systems require. Septic systems also tend to be less disruptive to the environment because they are not centralized systems with large outflow into single locations. Overwhelming nature is simply less efficient than using small, easily maintained septic systems.

We hope this gives you a little better understanding of how septic systems work. If you have any questions, please contact us. We would be happy to help.

Trust American On Site to take care of your septic system and we will be there when you need us. Give us a call to schedule an appointment, then just relax and let us do the work for you!

Contact us to learn more about our septic systems.