What is the Difference Between Septic Inspection Versus Evaluation?

The Missouri state septic program offers two different assessments for real estate transactions. The first and most comprehensive is a system inspection, while an evaluation is a less robust option that does not test the operation of the system. All things being equal, the preferred assessment, particularly of home buyers and lenders, is a septic inspection versus an evaluation. Although an inspection may be requested, given specific circumstances, an evaluation may be all that is possible. The primary criteria determining the type of septic assessment is the homes vacancy status. If a home has been continuously vacant for more than 60 days, or the home has a new septic system installed in the previous six months, a septic inspection cannot be performed. When a property sits vacant for 60 or more days without use of the drain and waste plumbing, the soil that comprises the treatment field experiences changes that adversely affect test results performed during an inspection. Specifically, soils in and around the absorption field may dry out, while the bio mat and biological treatment may become degraded. This results in the soil treatment field not responding to testing in the same manner as a system that has been in continuous use. Even after a home is put back into continuous use, a state inspection may not be performed for at least six months, in order to allow the soils and organics to reestablish. For the same reasons as listed above, newly installed septic systems cannot have a state inspection of operation, only an evaluation. Finally, in the event the septic system is shared between multiple properties and the soil absorption field is located on an adjacent property, an inspection is not possible due to the unknown usage rates of the other connected properties. The key difference between a state septic inspection and evaluation is the hydraulic load test. 

Septic System Hydraulic Test and Dye Tracing

A hydraulic load test injects a specified quantity of water into the septic system, usually through a man/port hole in the primary tank. The water injection is used to simulate the average daily sewage flow from the residence. The purpose of a hydraulic load test is twofold. First, the test determines if sewage and effluent can move through the septic system as designed, and second, can the soil absorption area successfully treat and safely disperse the waste water. A hydraulic load test should not be confused with a percolation test or soil evaluation which is used in the design phase of a new onsite waste water treatment system. The amount of water used in hydraulic testing is calculated based on the number of bedrooms in a home, with the exception of advanced dosed systems which must adjust the test amount to the size of a single dosing. Commercial onsite wastewater treatment systems are generally tested at fifty percent of their calculated daily flow rates. Indications of septic tank, or aeration treatment unit (ATU), failure include water backing up into the tank or home. An overflow indicates a clog or obstruction in the tank or downstream absorption field. Failure of the absorption field or soil treatment component include effluent or sewage surfacing in the yard indicating poor soils for the installed system, a high seasonal water table, or undersized system.

In addition to a hydraulic test, a state licensed inspector may recommend the use of dye to trace a system or further identify potential failures. Injection of fluorescent tracers may be used to identify the location of a previously unknown absorption field. More importantly, dye testing can be a powerful diagnostic tool to find septic tank or ATU cracks or failures hidden underground. Additionally, injected dye can be used to confirm if raw untreated sewage is indeed surfacing on a property. In addition to state licensing through the Department of Health and Human Service (DHHS), any septic inspector recommending use of fluorescent dye, must be water trace registered through the Department of Natural Resources (DNR). Regulation 10 CSR 23-3.060 further requires each separate dye injection to be registered with DNR. The Department of Natural Resources regularly utilizes dye tracers to conduct background studies such as tracking rivers, aquifers, and underground water formations. Fluorescent dyes have the ability to travel as much as 35 miles from the point of use. Dye injection registration is required to provide DNR a clearinghouse for all known dye injections being conducted in an area, so as to minimize any potential background interference of any DNR tests being conducted concurrently. Additionally, because of the unusual and bright color of most fluorescent dye tracers, frightened property owners may contact local or state authorities to report perceived environmental contamination. The clearinghouse can inform authorities of any recent dye test and therefore eliminate panic as well as costly emergency response.

State Septic Inspection and Well Water Testing

When conducting a state assessment for an onsite waste water treatment system, the inspector must identify if the home is served by a private water well. A private well is one that serves 8 or fewer residences. Wells serving more than eight homes, or community and commercial properties, are classified as public water wells. Public wells are under the jurisdiction of DNR and will not be tested. Homes served by private water wells are required to have a water sample drawn and submitted to a laboratory for testing. The purpose of the water sample is to assess any potential biological contamination from the septic system such as coliform or E. Coli. Additionally, the septic inspector must visibly assess the well head and casing to ensure the well meets minimum DNR construction standards, and DHHS setbacks from the onsite waste water treatment system. Specifically, the well casing must be properly capped with appropriate electrical fittings, and the casing must rise above ground to ensure groundwater cannot contaminate the well. The minimum setbacks from a septic tank are 50 feet, and 100 feet from any soil absorption field. The minimum setbacks are to prevent untreated sewage from entering the well before being treated in the soil.  Finally, well inspection can identify if a well has been abandoned and poses a potential health hazard. The most common hazards occur when an abandoned well provides a direct route for surface contamination to enter the groundwater.

A state septic assessment cannot be completed until the water test results are returned from the laboratory. Generally, results are returned within 24 to 48 hours after water sample submission. In the event a well water test fails, the property owner may chemically treat the well with chlorine in accordance with DHHS guidelines, and retest the well 5 to 7 days later, and again one week after the first retest. If both retests return normal results, the well may be deemed acceptable. 

Home Performance Group Septic System Installation Kansas City

Buyer a home and want to ensure the onsite wastewater system is in good working order? Concerned about contamination of your private well? Worried your septic system may be surfacing raw sewage? Consider septic system service by hiring a state licensed septic professional with advanced training to inspect, evaluate, repair, design, size, and install both basic and advanced septic systems. An upfront investment in careful assessment will prevent both health hazards and tens of thousands of dollars in future work.

At Home Performance Group we are both basic and advanced state licensed in septic system installation as well as state licensed for septic inspections. We continue to invest in technical training so we can correctly assess, design, specify, size and install septic tanks, septic laterals, low pressure systems, lagoons, and high-pressure drip systems. We have performed numerous septic projects for our clients.

If you are interested in a no-cost in-home consultation, schedule with a Solutions Advisor today. 

Article by Larry L. Motley Jr., 28 February 2022

Larry is a graduate of both Wentworth Military Academy and Missouri Western State University earning a double bachelor’s degree in Economics and Finance. Additionally, he maintains six professional tradesman licenses in two states and advanced credentialing in green technology, project and program management, and process improvement. Larry is a three-time combat veteran having served in Operation Iraqi Freedom, Operation New Dawn, and Operation Inherent Resolve. He continues to serve through a value-based building science company focused on providing clients the best design, highest quality installation, and most honest repair services in the community.