New Methods for System Monitoring: Part 2

The SepticSitter provides system information, general management guidance and is easy to retrofit to an existing system

New Methods for System Monitoring: Part 2

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This article is in a series focusing on new available technology to monitor septic system performance. As technology continues to evolve and costs come down, these tools will provide more in-depth information and should be considered by designers, regulators, installers and service providers. The second system we will investigate is SepticSitter (Dynamic Monitors).

The SepticSitter is a monitoring and early-warning alert system for onsite sewage systems. Sensors can be installed in septic tanks, pump tanks and drainfields. The sensors are connected to a hub that uses the internet service in the home or business. Data from the sensors can be viewed in real time from any internet-connected device, and all historical data is accessible for maintenance, decision-making or time-of-property-transfer inspections. Warnings and critical alert notifications can be emailed to the septic professional, system owner, regulator or any other interested stakeholders. 

Several sensors can be connected to the hub using a single string of low-voltage cables hidden underground. Sensors are mounted on a 2-inch PVC pipe and determine the liquid level and temperature in tanks and drainfields without contacting the effluent. Readings can be set to occur at a range of time intervals, typically every five to 30 minutes.

Figure 1: Septic system schematic showing sensor locations
Figure 1: Septic system schematic showing sensor locations
Figure 2: Typical gravel trench cross-section showing the sensor installed in the inspection port
Figure 2: Typical gravel trench cross-section showing the sensor installed in the inspection port


Figure 3 shows continuous drainfield levels and inspection port temperatures for the period from Dec. 11-27, 2017.


Figure 3: Actual drainfield levels and inspection port temperatures
Figure 3: Actual drainfield levels and inspection port temperatures

Some interesting observations can be made from an examination of the data:

  • Ponding levels (and likely effluent distribution) among the trenches is not very even. The inner trench near the center of the drainfield was consistently ponded the deepest, a minimum of 6 to 7 inches. Several times this trench filled completely to the top of the gravel.
  • On Dec. 19 when the inner trench filled completely, the middle trench suddenly started ponding 2 inches deep. This was likely a result of effluent spilling over from other trenches.
  • There were moderate rainfall events on Dec. 10-11, 13-14 and 24. These rainfall events appear to have triggered slight, temporary ponding in the otherwise-empty outer trench.

Six years ago, the owners of this property experienced a sewage backup in the middle of winter. They had to resort to an expensive "pump and haul" regimen for several months until a new drainfield could be constructed. They worried their new drainfield might fail catastrophically one day like their previous one did.

Figure 4: The SepticSitter sensor installed in an inspection port valve box
Figure 4: The SepticSitter sensor installed in an inspection port valve box

Once the sensors were retrofitted and detailed data was available, the homeowners were able to see that while the inner trench was full at times, the middle and outer trenches had excess capacity to receive effluent spillover from overloaded trenches. The homeowners have been relieved to know their drainfield is currently handling the daily flows from their home.

Alerts have been set up to provide automatic notification if ponding levels in the middle or outer trench start to approach concerning levels. If they do, their onsite professional will have time to propose a proactive plan to rejuvenate or upgrade the system before another failure occurs.

Key features of the system are:

  • SepticSitter can be retrofitted to all types of soil treatment units and sewage tanks.
  • Noncontact ultrasonic sensors won’t get “hung up” or fouled.
  • It uses existing internet service at home/business (a cellular internet option is also available).
  • Warnings, alerts and notifications are fully customizable from the online web application.

The system automatically detects problem conditions, allowing service providers early detection of potential issues such as effluent filter plugging or leaking plumbing fixtures. It provides system information, general management guidance and is easy to retrofit to an existing system. The SepticSitter system is another new tool for monitoring system performance and problem prevention.


About the Author
Sara Heger, Ph.D., is an engineer, researcher and instructor in the Onsite Sewage Treatment Program in the Water Resources Center at the University of Minnesota. She presents at many local and national training events regarding the design, installation and management of septic systems and related research. Heger is education chair of the Minnesota Onsite Wastewater Association (MOWA) and the National Onsite Wastewater Recycling Association (NOWRA), and serves on the NSF International Committee on Wastewater Treatment Systems. Send her questions about septic system maintenance and operation by email to kim.peterson@colepublishing.com.

This article is part of a series on monitoring technology:



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