Repairs
Connecticut Public Health Code requires that failed septic systems be repaired. Failure occurs when septic effluent is not absorbed by soils in the leaching area and breaks out to the surface or backs up into the house, thus becoming a health nuisance. Absent a health nuisance, there is no legal requirement to repair an improperly working septic system, or a system that doesn't "meet code" at the time of sale or at any other time.

Evaluations
It is customary and it makes good sense for sellers to warrant a functioning septic system at time of sale. That begs the question: Short of complete failure, how is the condition of a septic system evaluated? Although all parties in a sale want a quick and definitive answer, leaching systems wear out gradually and evaluation of how much life is left is often fairly subjective. Additionally, some kinds of septic system are harder to evaluate than others.

Evaluation is usually done during paid home inspections, which have become common prior to real estate sales. On occasion inspectors find evidence of problems with the septic system, but in many cases the evidence says little about the severity of the problem. Inspectors initially look into the septic tank. Septic tanks have an inlet and an outlet pipe and in normal operation the liquid should remain at the level of the outlet pipe. If the liquid is found to be above that level, it is an indication that the leaching system is accepting water too slowly and is close to failure.

More often the liquid level is at the proper level but there is evidence that it has been too high in the past (it leaves residue on the sides of the tank much like a bathtub ring). This may be evidence of present or past problems. When septic systems are repaired the tank is often left in place but the signs of past failure remain. Inspectors will not necessarily know if the evidence points to an active problem.

Inspectors will also try to evaluate the condition of the leaching fields. The ability of leaching systems to pass water into the surrounding soil degrades over time and some systems are more difficult to evaluate than others. Shallow systems can often be probed to see of they are saturated. If they are completely saturated the system is near failure, but for the test to be accurate, the inspector has to be able to find and probe all parts of the system. At times there is no accurate drawing (as-built) of the leaching area so it is hard to be sure all parts of the system have been inspected. Other systems are very difficult to test without substantial excavation and in those cases evidence of trouble at the tank may be the only diagnostic available. Additional testing might be advised but would not be covered by the cost of the traditional home inspection.

Reports
Given an inspection report showing an improperly functioning system, the next step involves a licensed septic installation contractor and the health department. In most cases "deep test pits" are dug to assess the soil conditions and space available for repair. The outcome is a plan for repair that is consistent with the Public Health Code (to the extent that is practical) and a quote for the cost of repair. In many cases time precludes repair, or even proper testing, prior to sale and all parties make some financial arrangement for later repair. All of this leaves buyers, sellers and agents with an imperfect system, but one better than no system at all.