Inspection Training

How to Inspect the Kitchen Sink Drain and Vent Systems

When the inspector is in the kitchen one of the first things that should be done is turning on the water at the sink(s) so they can begin to fill up while inspecting other portions of the kitchen. It is extremely important to check all of the piping below for any leaks after draining the water in the sinks and to use your hands on the pipes to check for those leaks. Please review the entire procedure below.


International Standards of Practice for Performing a General Home Inspection


3.6. Plumbing


I. The inspector shall inspect:

D. Interior water supply, including all fixtures and faucets, by running the water;

F. All sinks, tubs and showers and showers for functional drainage;

G. The drain, waste and vent systems.


II. The inspector shall describe:



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

C. Mechanical drain stops that were missing or did not operate if installed in sinks, lavatories and tubs.


IV. The inspector is not required to:



Axium SOP Differences

Axium Requires: The inspector should check the plumbing drain and waste systems underneath the kitchen sink by filling up the sinks and draining them simultaneously.


Tools Needed

The inspector will need to use the drain stoppers to fill up the sinks with water and might need to use flashlight to check underneath the sink.



  • When the inspector first starts to inspect the kitchen they should begin with putting drain stoppers in the sinks and turning the water on to begin to fill them up.
  • Make sure as the sink is being filled up you should be listening and watching the sink fill. Don’t get distracted and don’t leave the kitchen while the sinks are filling up so it doesn’t overflow (only need it to be half full). You can go around and inspect other items in the kitchen while the sinks are being filled up.
  • Look for leaks around the faucet, mount, and test the sprayer to make sure it is working properly. Also, make sure everything is mounted correctly, secured, and caulked.
  • After you have filled up both sinks you will want to take your first picture for this section which should be of the sinks filled up. This way we can prove to the clients that we did fill up the sinks and test for leaks

  • Next, pull the drain stoppers and turn on the garbage disposal. Immediately look under the sink for for any leaks and touch all water connections with your hand checking for leaks. Should be touching the pipes, supply lines, drain lines, hoses, and the garbage disposal. Now you will take your second picture of the drain pipes under the kitchen sink to show that there are no leaks present after you drained the sink.

  • The final picture that needs to be taken for this section is of the base of the cabinet below the drain piping to show there is no leaking or water damage. This picture needs to be clear and show as much of the bottom of the cabinet as possible so we have good documentation that there are no leaks or signs of previous leaks on the base of the cabinet. If there is a defect on the lower cabinet it should be noted in the cabinet section of the kitchen.


Common Defects

  • Drains that clog, leak, fail, or that are damaged or kinked.
  • Drains that are clogged, slow to drain, or missing.
  • Drains that have an “S” trap.
  • Traps that are missing or sloped incorrectly.
  • Drains that didn’t operate properly or hold water in the sinks.
  • Drains that are double trapped or have an improper connection.
  • Drains that are rusted or deteriorated.

Common Mistakes

  • During a flood test the drains underneath the kitchen sink will often leak. This is not your fault that it leaked but it is your responsibility to make sure that everything is dried up and the belongings under the sink are dried off. You will want to pull everything out to dry the base cabinetry and try to dry off all the bottles, boxes, etc. If there is something you see that is completely damaged or is causing a problem, you need to call the office right away so they can call the listing agent, so the listing agent can call the homeowner. Be sure to leave all items under the sink the same way that you found them.
  • Not checking the drain lines with your hands during the flood test of the sinks.
  • Not checking the supply lines for any leaking with your hands.
  • Not taking a representative picture of the drain lines and the cabinet floor below to show that there is no leaking or signs of previous leaking.
  • Having a flex drain line that could clog, leak, or fail but forgetting to call out as a defect.


Report / Software


  • The visible drain, waste and vent piping material for the kitchen 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.


  • Water Not On: The water was not on for the inspection. The inspector could not inspect condition 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.


  • The drain components were not installed under the kitchen sink. A qualified contractor should evaluate and repair or replace as necessary and according to current standards.


  • The [word 1] under the kitchen sink [word 2]. A qualified contractor should evaluate and repair or replace as necessary.
    • Identify:
      • Basket Strainer
      • Bathtub Drain
      • Dishwasher Drain Line
      • Drain
      • Drain Pipe
      • Drain Stop
      • Drain Stopper Linkage
      • Flex
      • Horizontal Section of the Drain
      • P-Trap
      • Shower Drain
      • Sink Basket
      • Sink Drain
      • Waste Line
    • Defect
      • Can Clog, Leak, or Fail
      • Clogged, Drains Slow
      • Clogs Easily
      • Damaged
      • Didn’t Hold Water
      • Didn’t Operate Properly
      • Didn’t Pop Up
      • Difficult
      • Disconnected
      • Double Trapped
      • Improper Connection
      • Improper Repair
      • Kinked
      • Leaking
      • Leaking @ Connection
      • Leaking @ Shut Off
      • Loose
      • Missing
      • Missing (Lever)
      • Rusted or Deteriorated
      • S-Trap
      • Slope (Incorrect)
      • Trap (Missing)
      • Was Kinked at the Garbage Disposal