SECTION 252:641-1-3. General requirements for on-site sewage treatment systems

(a)   Inspections. All new installations of, modifications to and/or repairs to on-site sewage treatment systems shall be inspected and approved by the DEQ, or installed, self-inspected and approved by a certified installer before new installations, modifications or repairs can be backfilled and/or before the system may be placed into operation. The installer shall be responsible for requesting any required DEQ inspections.

(b)   Treatment. On-site sewage treatment systems shall only be used for treatment of sewage, as defined in 252:641-1-2. All sewage must be treated and dispersed according to the rules in this Chapter.

(c)   Ownership. An on-site sewage treatment system shall be located only where:

(1)   all components of an individual on-site sewage treatment system, which includes tanks, pumps, dispersal fields and collection line(s), are or will be located on property that is:

(A)   owned by the owner of the on-site sewage treatment system; and/or

(B)   dedicated in a recorded easement for the installation and operation of the on-site sewage system to the owner of the on-site sewage treatment system; or

(2)   all components of asmall public on-site sewage treatment system, excluding service lines, are or will be located on property that is:

(A)   owned by a municipality, rural water district, rural sewer district or federally recognized tribe; and/or

(B)   dedicated to a municipality, rural water district, rural sewer district or federally recognized tribe in a recorded easement for the installation and operation of the on-site sewage system; or

(C)   owned by the owner of the small public on-site sewage treatment system.

(d)   Minimum lot size. The designer and installer shall comply with the minimum lot size requirements as set forth in Appendix A, Figure 3. Plats recorded before January 1, 1974, are not subject to minimum lot size requirements but systems installed in those platted areas must meet the construction requirements of this Chapter.

(e)   Requirement for a dispersal field or lagoon. All on-site sewage treatment systems shall utilize one of the dispersal fields described in Subchapter 12 or a lagoon described in Subchapter 15.

(f)   Average daily flow.

(1)   Individual on-site sewage treatment systems. The average daily flow for an individual on-site sewage treatment system shall be based on an average water usage of two hundred (200) gallons per day for a residence of two (2) bedrooms or less, with an additional sixty-six (66) gallons per day for each additional bedroom.

(2)   Small public on-site sewage treatment systems. The average daily flow for small public on-site sewage treatment systems shall be calculated using the estimated average daily flows listed in Appendix F, unless actual flow data or a more accurate estimation method is available or there is seasonal flow variation. When there is seasonal flow variation, the average daily flow shall be calculated using the highest monthly flow in the previous twelve (12) months divided by the number of days in that month.

(g)   Sizing. All dispersal fields and lagoons shall be sized based on average daily flow using the charts in Appendix H. The size of on-site sewage treatment systems should be increased if the actual or anticipated water usage exceeds the above-stated average.

(h)   Separation distances. The designer and the installer shall comply with the required vertical separation distances in Appendix A, Figures 1 and 2, and the horizontal separation distances listed in Appendix E.

(i)   Pipe specifications. All pipe used in on-site sewage treatment systems shall meet or exceed the minimum specifications listed in Appendix C.

(j)   Water body restrictions. No dispersal field may be installed within Zone 1 of a water body protection area unless it is preceded by a nitrogen reduction system that has been tested and certified by an ANSI accredited third party certifier as meeting the most current NSF/ANSI Standard 245.

[Source: Added at 16 Ok Reg 1895, eff 6-11-99; Amended at 18 Ok Reg 1616, eff 6-1-01; Amended at 19 Ok Reg 1704, eff 6-13-02; Amended at 21 Ok Reg 1618, eff 6-11-04; Amended at 25 Ok Reg 2318, eff 7-11-08; Added at 28 Ok Reg 1278, eff 7-1-11; Amended at 29 Ok Reg 1053, eff 7-1-12; Amended at 37 Ok Reg 1296, eff 9-15-20]