You have read here on several occasions about the City of Davison’s I/I Program. Over the past few years the city has taken an aggressive position in attempting to disconnect any non-sanitary connections to our sanitary sewer system.

You may have read in past blogs of my agitation to State and Federal non-funded mandates to local governments. These mandates sometimes seem to be nothing but busy work sometimes due to the fact we, at the local level never see the impact of what we are doing.

I/I (Inflow and Infiltration) is one of those non-mandates, or is it?

At our last City Council meeting we had good discussion on our ordinance that deals with these disconnections from our sewer system. Chapter 1044 of our code deals with sewer regulations.
The details of this discussion are important to today’s blog. Although that discussion has created a lot of communication/questions among Council Members, staff and some general public.

What I found interesting is our city’s lack of ability to communicate this story to the public. This is not new. The City of Davison is not alone with this issue of getting the word out. But…if we look at the history of I/I it would look something like this:

  • Until the late 1960’s the popular thought on sewer treatment was that the solution to pollution was dilution. An other words, if we dilute the sanitary sewer system with rain water it will be easier to breakdown and produce the cleaner outflow at our Sanitary Sewer Treatment Plants.
  • Until this time it was normal to hook up a homes weep tiles (the drainage tiles that are under your home and remove any rain water away from your home as the rain water follows your basement walls down into the ground) to the Sanitary Sewer System.
  • In about 1967 the Building codes or regulations changed not allowing the above to happen.
  • Around 1970 the City of Davison did its first I/I study which resulted in the above linked Ordinance (1972).
  • In the 1980’s the city performed another I/I study which led to placing collector tiles behind some curbs to make it easier for homeowners to disconnect their weep tiles, down spouts and sump pumps from the Sanitary Sewer System. This was a voluntary disconnection program and from what I understand only a half dozen or so homes participated.
  • The late 1990’s the Federal Government mandated that Sewer Operations disconnect any cross connected systems.
  • The City of Davison started our third I/I study.
  • We have found that we have major I/I system issues. Our normal system treatment charges are $15,000-$16,000 per month. In a wet month (January had unseasonably warm up and some rain) our sewer fees are around $36,000. In a real wet month (one or two months per year) we pay as much as $80,000 for sewer treatment.

So as far as unfunded Federal Mandates go, this one the feds have given us a little notice to change (around 40 years).

This still doesn’t make the solution easy, and that is what we are working on now. The hardest part is funding an entire project (around $20 million). The second hardest item is getting the story out. We have had 40 years to explain it and we must do better, we already have Ordinances on the books to change over to a more efficient and less costly system. It is taking the next step that gets difficult.