When Existing Systems Require a Compliance Inspection

The level of complexity grows when you move up from a more basic operation inspection to a compliance inspection. Follow these steps to ensure you cover all the bases.

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There are several reasons an existing onsite system would require a compliance inspection. A number of states — Minnesota included — require the local permitting authority to establish an inspection program to bring failing or non-code systems up to compliance over time. Also, homebuyers often request compliance inspections before purchasing the home to be assured the septic system meets the current standards and requirements.

Compliance inspections of existing systems are a level beyond the operation inspection, where the system is checked to determine if all the components are there and operational, which is the level of inspection most often seen in terms of real estate transfers. From a service provider standpoint, the compliance inspection is more comprehensive, so it will require more time and effort and therefore command a higher fee.

Look at Tank Contents

The sequence for inspecting system components and the items evaluated will look similar to the operation inspection, but will go a step or two further in the assessment. All sewage tanks are going to be inspected to determine whether they are watertight and structurally sound. This means evaluating the walls, the bottom of the tank and all penetrations, including the inlet and outlets as well as the tank lid, manhole risers and inspection ports. In our opinion, this means the tank will be pumped to provide access for the evaluation. Before pumping, the contents should be evaluated for conditions that may indicate other problems, such as evidence of previous backups or lack of three distinct layers.

The inspection ports and manhole should be evaluated in terms of their location as well as any cover or access restriction requirements to keep unauthorized persons from entering the tank. Baffles within the tank should be checked for their presence and condition as well as whether they have the proper space between the pipe and the baffle wall and proper depth within the tank. Presence of an effluent screen should be determined.

If there is a pump tank it should be evaluated for structural soundness and the pump and controls evaluated to verify the pump has adequate capacity to deliver effluent to the next system component. Controls and electrical connections should be checked to determine if they meet electrical code requirements. Connections should be in a box or control panel outside of the tank.

These are the same items checked during a new system inspection. In an operation-level inspection the inspector checks to see everything is there and the pump turns on and off, and connections are proper, but does not go so far as determining pump doses and capacity.

Down and Dirty

The area of greatest difference in level of inspections comes in evaluation of the soil treatment area. During an operation inspection, the drainfield is evaluated for surface evidence of hydraulic failure and that effluent does not back up into the tank. Compliance means the soil treatment area is the right size based on soil, texture, structure and estimated daily sewage flow. In addition, the area needs to comply with the required horizontal separation distances and vertical separation distances required for treatment.

The soil texture and structure in the area of the system needs to be determined to supply the long-term acceptance rate for the soil, which can be used with estimated daily sewage flow to determine the necessary system size. If records of the site evaluation and system design are available, information gathered in the field can be compared to those numbers to see if they match. If there are no records, this inspection provides the baseline information for future comparison.

Similarly, vertical separation, to a limiting condition such as bedrock or high water table must be determined. In the case of water table or seasonally saturated soil conditions, this requires the evaluation of soil color to determine if there are redoximorphic features. These features indicate — even during dry periods — the presence of saturated soil conditions. The separation distance is determined by measuring from the highest point in the profile where redoximorphic features are indicated to the elevation of the bottom of the drainfield or bed in an elevated system.

A note here; in Minnesota for a compliance inspection of an existing system, the state code stipulates that two independent entities need to make the determination of soil condition. One of these can be the initial site evaluator’s information; but if there are not records, there would need to be an independent verification. As example, a compliance inspection is conducted by a county or municipal licensed inspector and a determination made to update county records. Presumably this would need to be confirmed through an independent evaluation by another licensed inspector.

Difference of Opinion

This can lead to some disagreements, so there is also a requirement that the county or permitting authority establish a way to resolve any disagreements in the evaluation. This is an important provision since there is often some level of disagreement among professionals about soil interpretations. As we see it, though, recognize that once you move on from an operating level inspection there is a significant jump in time effort and resources to determine if the system is in compliance with all code requirements.

As we travel around the country we see many areas where inspection requirements have not been fully addressed. Usually these are the places that just now or recently (the past decade or so) have moved to requiring inspections and records at the time of new installation, but lack records for all the existing systems previous to current rule updates and requirements. This is why it is important to understand the differing levels of inspection and what each requires.


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