Inspection Training

How to Inspect the Plumbing Drain, Waste and Vent Systems

While the inspector is in the crawlspace or the basement the drain, waste, and vent systems should be evaluated. If there is any leaking or damage it should be noted in the report under Repair/Replace and the inspector would have to write that comment in themselves. If the drain lines are not visible the inspector should use the “Not Inspected” comment. Please review the entire procedure below.


International Standards of Practice for Performing a General Home Inspection


3.6. Plumbing


I. The inspector shall inspect:

G. The drain, waste and vent system.


II. The inspector shall describe:



III. The inspector shall report as in need of correction:



IV. The inspector is not required to:

L. Determine whether there are sufficient cleanouts for effective cleaning of drains. N. Inspect wastewater treatment systems.

Axium SOP Differences

Axium Requires: Same as NACHI Standards of Practice.


Tools Needed

No tools required to inspect the plumbing drain, waste and vent systems.



  • The inspector should check and observe all the visible drain, waste and vent systems at the property the material being used for the drain lines. These will most likely be located in the basement and/or crawlspace. Sometimes these drain lines won’t be visible if everything is finished and there is no crawlspace.

Common Defects

  • No defects for this section. NOTE: Even though there are no specific defects listed in this section within the software the inspector should still make a note in the report under Repair/Replace if there is any damage or leaking found at drain lines in the crawlspace or basement. All other issues with drains will be noted specifically in that section, i.e., kitchen sink, bathroom sink, etc.

Common Mistakes

  • Not checking all the drain lines in the basement and/or crawlspace.
  • Not identifying the correct type of drain line material.

Report / Software


  • The [word 1] visible drain, waste and vent piping material was in satisfactory condition and was functioning as designed and intended. The drains from all functional fixtures were tested during this inspection, and each emptied in a reasonable amount of time and did not overflow when other fixtures were drained simultaneously.
    • ABS
    • Cast Iron
    • Cast Iron, Lead, and PVC
    • Cast Iron, PVC, and ABS
    • Copper
    • Lead
    • PVC


  • Water Not On: The water was not on for inspection. The inspector could not inspect conditions of faucets, fixtures, plumbing, pressure or volume. Once water is restored to the property a qualified contractor should fully evaluate the plumbing system and repair or replace all areas as necessary.


  • N/A


  • N/A