Septic Inspection: Is Dye Test Needed?

plumbing, septic system, basement drain

I listen to your show on WCBS 880 in NY and understand you spent many years as a home inspector.  We are buying a ten year old house in Fishkill NY. We had the house inspected last week; however the home inspector would not check the septic system with color dye. He stated that the fields ‘looked okay.’  Would you insist on him doing the test? Chris – NY

Well, yes and no!  I’d definitely insist upon having a septic inspection done but I’d pass on letting this inspector do it!  There’s just no way a system can simply “look okay” unless a minimally thorough septic inspection is done.  And while a septic system evaluation is not a required part of a standard home inspection, any home inspector offering that service has the responsibility to do it right or not do it at all.

In my home inspection business, most of the homes we inspected had city sewers.  In the occasional house that had a septic system, I regularly declined performing this additional evaluation, preferring to leave that up to the folks that did them all the time. 

For a state of the art look-see into what a present-day septic inspection should entail, I turned to Joe Corsetto, Past President of the American Society of Home Inspectors and a Registered Environmental Health Specialist with the State of New Jersey.  Joe says that dye testing, is inadequate in almost all situations, except near water when it can help spot a leak into the waterway.  He recommends that a thorough septic inspection include the following four steps at a minimum:

  • Each septic system component should be located and opened to perform a visual check of its function.  This is an absolutely essential element of all thorough septic inspections.
  • The gravel disposal field, laterals, seepage pits (older systems), and other elements must be probed to determine the presence of abnormal saturation. The home’s plumbing system must be run enough to simulate usage (known as volume loading).
  • And, inspectors should perform a record check at the municipal Health Department.  This can help identify all sorts of concerns including proper permits, plans, complaints, etc.

A septic inspection as described above should cost $450 – $650, which while significant, can help you avert septic system repairs costing far, far more.

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