Why Is It Like That? Field Testing the Onsite Wastewater Treatment System Assessment Tool
Our Water & Public Health team at the Illinois State Water Survey developed an Onsite Wastewater Treatment System Assessment tool (OWTS tool) in 2023, with technical assistance from the Rural Community Assistance Partnership (RCAP) and the National Onsite Wastewater Recycling Association (NOWRA) and funding from the United States Environmental Protection Agency (US EPA). This tool is a companion to the Well Assessment Tool, which was also created with support from RCAP and funding from the EPA. Both tools have been used extensively by RCAP technical assistance providers (TAPs) and other health professionals to evaluate private wells and septic systems.
The basic function of the OWTS tool is to collect critical information such as landscape and geology details, general details about the system and property, and maintenance/repair records. The goal is to comprehensively understand how a system is being used so that potential vulnerabilities can be identified, and the most appropriate education, information, and recommendations can be provided to the homeowner.
We have previously detailed a field expedition by our staff to conduct OWTS assessments on the blog at our sister program, WaterOperator.org. In this latest field assessment summary, we are assessing the system on the property of one of our team members in Piatt County, Illinois.
Here is an example page from the OWTS assessment:
(You can find the entire assessment document to download, fill out, and print as needed here.)
Our staff member’s septic system is an aerobic treatment unit (ATU), and the house it serves is over 100 years old (built around 1910, originally as a one-room schoolhouse). The system is somewhat unique for a number of other reasons, which made assessing the system something of a challenge. First; there is no record of it whatsoever at the local health department, indicating that permits were not filed to install it and that it was likely a DIY job done by a previous owner. While that leaves open a lot of questions about the age and history of the system, from the information we can gather it seems this was likely done around 2014.
The system’s tank is also much larger than it needs to be for the house, which has only two bedrooms. Furthermore, the chlorine chamber is installed about 80 feet away from the tank. Without plans and records from the installation available, it has been difficult to pin down a reason why the chlorinator and septic tank are so far apart. Between the tank and chamber is a chicken coop and run, which would appear to be a possible reason why. But historical satellite imagery accessed by our staff member suggests that the chlorinator in its present location actually predates the construction of the chicken coop.
The drainfield lies an additional 80 feet beyond the chlorinator, on a slight downwards slope. It is also unclear as to why this distance is so great. Finally, there are also some open questions concerning how much of the house’s greywater is reaching the septic tank. This is still being explored as well.
Here, we can see the tank’s manhole and the fake rock which houses the air pump and the system alarm. When the tank was serviced in March (for the first time in our staff member’s ownership), it was found that the air pump was not functioning. The pump has since been repaired and the 900 gallon tank pumped out.
Here, we can see the chlorinator, which abuts right up against the chicken run. The chlorine tabs have also been recently replaced.
FInally, at the far end of the property, we can see the area of discharge. The outlet pipe is underneath the pile of wooden debris left by the previous owners, which made it hard to locate initially. According to the septic maintenance workers that worked on the system in March, this type of discharge area is no longer allowed. But, existing systems were grandfathered in after this rule change was made.
While we have our theories on some of the puzzling elements of this property and its septic system, we still don’t know anything quite for certain. If you have any theories, or any questions, email us at info@decentralizedwastewater.org. We would love to know what you think!
Furthermore, at our sister program’s Private Well Conference coming up in May, we will be going over this unique case study in more detail during one of our technical sessions: “Onsite Wastewater Treatment System Assessment Tool: Lessons from Two Case Studies.” If you’re going to the conference, we especially encourage you to take the opportunity to tell us in person what you think might have been going on when this septic system was installed. And, if you’re not currently registered for the conference, there is still time: Registration will close in early May!
In the meantime, you can find the OWTS assessment in addition to the private well & spring assessment tool on the Private Well Class website.
Homeowners can contact their local RCAP office to request a technical assistance provider perform an assessment on their wells and/or septic systems.
You can also get more in-depth information on how these assessment tools work from our webinar recording: Conducting Private Well and Onsite Wastewater System Assessments.