NAWT Onsite Wastewater Installer — Level II Practice Test
Build your confidence for NAWT Onsite Wastewater Installer — Level II. Practice the concepts, understand the answers, and strengthen your knowledge one question at a time.
Try a sample questionExam overview and details
The NAWT Onsite Wastewater Installer - Level II exam is a professional certification assessment designed for experienced installers seeking to validate advanced competency in the field. This 48-question examination tests comprehensive knowledge beyond basic installation, focusing on complex system components, site evaluation integration, advanced treatment technologies, and regulatory compliance. Candidates should have substantial field experience and foundational knowledge equivalent to a Level I certification. Successful completion demonstrates mastery in sizing and installing sophisticated systems like aerobic treatment units (ATUs), media filters, and drip dispersal systems, as well as proficiency in interpreting soil and site evaluations to ensure proper system function and longevity. By earning this credential, professionals signal to employers, regulators, and clients their commitment to industry best practices and their capability to handle challenging installations that protect public health and water resources.
Sample Questions
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During a site evaluation, you perform a percolation test. Which of the following conditions, if observed during the test, would invalidate the results and require the test to be stopped and re-scheduled? (Select all that apply.)
During a percolation test, you observe that the water level in a test hole drops 2.5 inches over a 30-minute period after the prescribed pre-soaking. What is the calculated percolation rate in minutes per inch, and what general soil permeability category does this indicate?
During a routine inspection of a conventional septic system, you observe that the scum layer in the septic tank is 8 inches thick and is within 2 inches of the bottom of the outlet baffle. What does this observation most likely indicate, and what is the required action?
An installer is reviewing the as-built drawing for a system installed 10 years ago. Which THREE pieces of information are MOST critical to locate on the drawing before conducting a routine inspection or planning a repair?
Hillside Installation A property owner on a steep hillside (25% slope) needs to install a conventional septic system. The soil evaluation shows a restrictive layer at 36 inches depth, with suitable soil texture above it. The daily design flow is 900 gallons. The installer must determine the appropriate drain field configuration.
Which of the following installation methods would be MOST appropriate for this hillside site to ensure proper effluent distribution and prevent surfacing?
Career Opportunities & Salary
Exam insights and study advice
Mastery of Level II concepts directly translates to installing systems that function reliably for decades, prevent groundwater contamination, and avoid costly callbacks and failures. In the real world, this knowledge ensures that complex sites with poor soils or space constraints can be safely developed, protecting property values and public health while maintaining compliance with increasingly stringent environmental regulations.
Recommended
These are the backgrounds the certifying body suggests. Check the vendor's own page for anything it formally requires.