You Should Know These Basic Onsite Design Principles

Every onsite professional should have a basic understanding of the entire system design process.
You Should Know These Basic Onsite Design Principles

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One of the principles established by our colleague Roger Machmeier at the University of Minnesota was that no matter what role you played in the onsite industry, everyone should take part in the same education programming, covering all aspects of the systems.

The premise – and we believe it was a good one – was that having all professionals represented at the same sessions made the workshop content better and more important. Whether participants were state or local government officials, site evaluators, designers, inspectors, installers or service providers, having a variety of perspectives made for a better understanding of the problems that each group faced. This better understanding carried over into the field and the result was better and longer-lasting systems. 

This model worked well in Minnesota for a number of years. However, there was always a certain amount of resistance from individuals – particularly on design issues where math and calculations were involved. We experienced even more pushback when we took our workshops using this philosophy to other states. The response went something like this: “I only have to know this because someone else is responsible for that. And besides, the state or local government does not allow me to perform that role.” Depending on your own context, you can fill in the blanks of what this and that referred to.

Specialization rules

In two decades, numerous changes in our industry have made it virtually impossible for professionals in all segments to take part in all training programs or workshops. Think of all the new technologies that require very specialized training for installation, operation and maintenance. There is much more emphasis on evaluating landscape position and soil characteristics requiring specialized training in describing soils. The list can go on and on.

So it is probably not realistic that everyone knows every detail about each function. On the other hand, it is important that people working in all areas start out with a basic understanding of how each part of the system is supposed to operate, how to tell if there is a problem, and what can be done to solve it.

It is not appropriate for an inspector to say to a designer or installer, “I will not allow you to put the system in that way because I have not seen it before and I do not know how it works.” If the installer or designer has had specific training, they need to share that with the inspector and come to an agreement about moving forward. Likewise, an installer should not be able to hide behind, “I only put systems in according to the design plans and it is not my fault that the soils were not identified correctly and the system failed.” 

This is why we have recently worked with the National Association of Wastewater Technicians to develop a course that addresses the principles of design outside the context of specific state codes. It looks at design work from the standpoint of what is needed; how each element of design affects the choice of a system for the site, and how the user (homeowner) impacts whether this is the right system for long-term use.

The idea was to do for design what we did for installation years ago, boiling it down to the KISS, KINN, KILL and KIDD principles. If you have forgotten what those acronyms stand for, remember that you can come up with a creative word to match the last letter to help get your point across. KISS is Keep It Shallow ______; KINN is Keep It Natural ____; KILL is Keep It Level _____; and KIDD is Keep It Dry _____.


This workshop developed with NAWT combines classroom presentations with field exercises in each of the need to know categories for design. We submit the following know principles for consideration.  

1. Know the permit requirements: If you do not know the rules to begin with there will be problems with the permitting authority.

2. Know the risk involved: Is the area a nitrogen management area? Are there environmental or health risks associated with the site?

3. Know the user: How they use the system designed can impact whether it is a success or failure.

4. Know the soil: Most system failures can be traced to misidentification or misapplication of soil characteristics.

5. Know the collection method: How does the sewage get where it is supposed to go?

6. Know the delivery to the soil: Does it get to the soil by gravity? By pressure? How?

7. Know what it takes to care for the system: What are the operation and maintenance requirements? How does that tie back to the risk factor?

Hopefully we have set the stage for discussions around each of these basic principles. If you feel we have missed some principles along the way please feel free to share them with us. Comment below or send an email to


Jim Anderson, Ph.D., and David Gustafson, P.E., are connected with the University of Minnesota onsite wastewater treatment education program. David is extension onsite sewage treatment educator. Jim is former director of the university’s Water Resources Center and is now an emeritus professor, as well as education program coordinator for the National Association of Wastewater Technicians. Readers are welcome to submit questions or article suggestions to Jim and David. Write to


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