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65.08   SETBACKS.
Setbacks more stringent then the IDNR requirements have been established by Story County to enhance water quality protection. The current setback requirements for the IDNR are shown in parentheses in the table below. The more stringent setbacks apply to all new septic installations in Story County installed after January 1, 2021. Owners who have limited options for system placement may request, in writing, a variance for this requirement to the Sanitarian. Appeals of the Sanitarian's decision will be heard and voted on by the BOH.
Table 1
 
Minimum Horizontal Distance in Feet From
Closed Portion of Treatment System *
Open Portion of Treatment System**
Private water supply well
50 (50)
100 (100)
Shallow public water supply well ***
200 (200)
400 (400)
Deep public water supply well ****
100 (100)
200 (200)
Groundwater heat pump borehole
50 (50)
100 (100)
Lake or reservoir
50 (50)
100 (100)
Stream (Class Al, A2, and A3) or pond
25 (25)
50 (25)
Edge of road ditch
10
10
Edge of drainage district ditch
25 (10)
50 (10)
Dwelling or other structure
10 (10)
20 (10)
Property lines (unless a mutual easement recorded)
10 (10)
10 (10)
Other type of subsurface treatment system
5 (5)
10 (10)
Water lines continually under pressure
10 (10)
10 (10)
Suction water lines
50 (50)
100 (100)
Foundation drains
10 (10)
10 (10)
Subsurface drainage tiles
25 (10)
50 (10)
* Includes septic tanks, aerobic treatment units, fully contained media filters, holding tanks, and impervious vault toilets.
** Includes subsurface absorption systems (secondary and tertiary treatment), mound systems, intermittent sand filters, constructed wetlands, open bottom media filters.
*** Shallow well means a well located and constructed in such a manner that there is not a continuous layer of low­permeability soil or rock (or equivalent retarding mechanism acceptable to IDNR) at least 5 feet thick, the top of which is located at least 25 feet below the normal ground surface and above the aquifer from which water is to be drawn.
**** Deep well means a well located and constructed in such a manner that there is a continuous layer of low-permeability soil or rock at least 5 feet thick located at least 25 feet below the normal ground surface and above the aquifer from which water is to be drawn.