City FDD Survey (I): Wet Basements after 26% of Dry-Basement FDDs

The City has released the preliminary results of a survey covering all homes where FDDs have been performed under the mandatory FDDP. The numbers are appalling, including this one: FDDs caused wet basements in 107 of 411 basements that were dry before the owner’s FDD was completed. That is 26%. We’ll discuss that in this post and then cover two other numbers in the next–continued sewage backups in homes with FDDs that had sewage backup problems pre-FDD and survey responses concerning emotional damage from FDDs.


As part of the City’s FDDP Effectiveness Study, OHM and Project Innovations, it’s “public engagement” subcontractor, have now concluded a survey of the post-FDD experiences of over 2,300 homes in Ann Arbor over more than 12 years. Here are three particular points from the preliminary results that stand out:

  • Out of all respondents (a total of 411 homes) who reported having no “flooding/seepage/dampness prior to FDD,” 26% reported that they “experienced flooding/seepage/dampness after FDD” (for a total 107 homes).
  • 39.68% of respondents reported an increase in anxiety.
  • 27.64% who experienced sanitary backups prior to FDDs are still experiencing backups.

Given the above, it’s not clear why the City and OHM have not already discontinued any further study of FDDs. Just on the face of even their raw partial data, the FDD procedure is dangerous to people and property and merits a moratorium, not a study about doing more.

Based on the preliminary survey data, it’s looks as if the City’s solution to 200 residential sewage backups before the FDD Ordinance over 12 years ago has been to create 107 wet basements (and counting) with FDD installations. The survey has not been completely tabulated, but we think it’s likely that survey will show more flooding—well over the number of 200 residences in 2001–while the City proposes to do more.

26% Dry-Basement Flooding Rate

a2underwater has questioned the basic plumbing and physics of FDDs in postings at  a skepticism you should now share. Though I am not particularly surprised at a high dry-basement flood rate, 26% is off the charts.

OHM has already endorsed the survey results and said to the CAC that it has 99% confidence in the survey results. The survey is intended as a tool for assessing the the wisdom of FDDs in 18,000 more FDDs in pre-1982 one-family homes in the future.

The 26% dry-basement flood rate strongly implies that if the City-required FDD procedures that have already been performed in 1,834 homes were to be repeated under the FDDP in a mere 5,000 of the remaining dry basements in Ann Arbor, 1,300 of those basements would have water damage. We are sure more than 40% of those residents have had their anxiety level further raised by the FDDP.

So the the first result of the survey, it seems to us, is that FDDs are extraordinarily prone to flooding dry basements and and cause anxiety levels they are willing to report.

FDD programs are one of OHM Advisors big business lines. FDD programs are extremely lucrative sources of revenue for companies that used to make their money digging drains and sewers for cities no longer willing to upgrade infrastructure.

If the City and OHM say that FDDs will remain on the table at the CAC, how would OHM propose that the City do those FDDs without providing a clear warning to the homeowner of the flooding risk and the risk of emotional stress? That wouldn’t be negligence or gross negligence. That would be malice.

Remember, this is a program that already has a long factual record on malice, including the many consistent claims of overbearing tactics by City contractor personnel, the long record of disinformation about the FDDP from the City and its contractors, and a history of “public engagement” in the Target Areas that many people call “divide and conquer.”

Next Post: Sewage Backups and Emotional Distress

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